May 1982
The independent magazine for the independent user
Discover how
theZX-81 is
manufactur
BUG -BUTE
Till 1 TIM',
The lan-.p I Rni the Beast
h game of concentration and sua pence- in which you, the
intrepid hero, must wandar lii the darkness ami
of the Beast's palace, find the 3ai»el hiding or Imprisoned
there, kill t>ir> Beast, and* then last fcut nftt least, lMd
the DB.nF.el to the pilaca exit before Rhp starves to death.
Af) extremely comply, tlpg and entertiinirv' jraim.
jrlce Ci ■
■ t T
Tfou t bseome the 1,'qth jrasident for life of th*
atate of hltimha, The abject of your rut* Is tc do what
all previous president, failed to do, that in, to -
advantage of the 6 ituation. far your awn good ,
The program in supplied on high quality o- tcgrthw
with an ■'■■ pepf- booklet containing detailr-
1ns tract lore and hint.-.
Price i3 t Q0
r.taF Trek
The classic computer game in which you trek acroee the
Galaxy in search of Oiagons to zap ml jttfwsrs and
photon torpedoes. You have long and short range acinn<--r
help you find them, l-tarhaseF. to refuel your ship at and,
3f course, vaxlauE witty comnentn • -.raw
ei -■ T6-50
■-■ of UnumjE
Another fant,s..tlc ad '/entiir*
for the I-
INVADERS
■ !ng, maeii'- y^z-lan of th* famous arcade
ga»e, for tli ft ■ ■ i r> J-1-- lr e provided to hei ,
you from the i ".he n&rching aliens. Ten levf-
uicidsl. Lin screen
Price only jt.4,00
s=$S
TE UTILITIES
ZXAS «
□a
This full specification .:4C Assembler afiOomblc^ all the
Standard Zllaa mnemonics, which are- simply written into
fi-K ■ tate«?nt!i within your BVin program. then asser.hled,
the assembly listings, together with assembled coder. and
addnscir.er- are displayed on the ■sepeen. The ajJ8«Bb]*d codes
and addresses, are dis played r*i the scrawl. The assembled
code 19 eitecutcfl by !fR, The program occupies; %. This
means that /-U£~- maybe used in C on Juneti on wit'
The Effopran is available for both the 16K H.il and the
3K ROH ZXBO. ■■'nil documentation cm h:M to U&e the
assembler (including a list of the mnemonic:: ) i£ supplied;.
ZXDB
^.je
The perfect complement to the ZXA3 assembler, JOS
la a complete combined machine code (Ji-^ar^entilej- and
debugging progrufl] .
Ajart from the Ml \ ' rHi.-E, the program, has featuref. inc
Including 5D*Gi£ ETvF, BUEK "JiAJSCH. THAlEra AH? FILL,
HEX tf)tf)ER. REGISTRY DEPU1 and more, all of which are
esecutad by simple one key command!; mm the keyboard.
ZXTK
rft.oo
Oil enhances the facilities offered by ZXSl B/SXC -
a must for the serious R\T[(] [irogrammer . Includes, full
re -numbering, the ability to maJlipuliiti- groups of liner-
and merge files, read filename!-, from tapes and more.
REINJUM
£4.00
Henu* fci a full renumbering progmm , HcnumberE'. Ham
umbers, GOTtki Wld GtEUBa, and will renumber ax biting
pr>-rpn.w..
BUG-B8TE
mm\ imns
l"rogram lAok
1
iToffram lack
Z
itogram lack
T
^.50
frogram ia-ek
>l
£4.50
Progpaa lack
•
£4.50
nil rack
■
Oograa tacfe
7
frogram Einck
ETHIfSS
Multifile
A mtiM.ipurpOGe filing syEtem for the MA *":. t wIAm rangB
of pcBsible applications.
:Tice £l?.5fl
Videograph
■ileal display and t**ting program. Hundreds of pH«lble
applications.
Irrice £7,50
Vir-wteat
JTice 17.00
'"liatiwi
Turn yourr axfll into a teles eope. Gives an accurate
repreBentatlon Of the nifftit flky rm any date of th*
Century ,
.-rice £8 .00
contents
sindair
Editor
Nigel Clfirk
Consultant editor
Mike Johnston
Product ion editor
Harold; Mayes
Design
William Hcolding
Ad verti s*m ent director
Simon Hor,«an
Editorial director
itei In i }\\
Advertisement manager
Les Morton
Editorial .'production assistant
Mafgarel Hawkins
Managing director
Terry Csrrwrlghi
Chairman
i d J lease
Sinclair User is published monthly
byECCPuhlicationsLld.lt is not in
anyway connected wilh Sinclair
Research Ltd.
ephfitie
Ml departments
01-3587481
ll you would like 1 tilnhutelo
Sim lair User, please send typed [or
bea ill i I ulK- h nnd written) articles or
prog rams in —
Sinclair I
Publications,
: Islington Green,
London Nl8B|
We will pny £10 for each program
printed and £50 for each article
which should be approximately 1,000
rds long.
ipyrighlieaz
Sinclair User
ISSN No 0202-545B
Printed and typeset by
Boumehall Press Ltd,
Welwyn Garden City.
Dislribuled by
Spotlight Magazine Distribution Lid,
1 Benwell Road.
Kolloway,
i nndonN?
01-807 6411
5 SINCLAIR VOYANCE The new Sinclair machine, the ZX-Spectrum. is expected any
minute now. We peep al ils facilities.
7 HARDWARE WORLD A whole batch of hardware goodies examined by
ou r ad d-on a xport.
II SOFTWARE SCENE As more and more software floods on to the market,
we lest a few programs for your delect ation.
15 HELPLINE Andrew Hewson, the Marjoric Proops of Ihe ZX world,
answers moreof your problems. This monlh he tackles numbers.
17 LETTERS Your letters have already started to roll in and we present a
selection.
16 ADVENTURE GAMES Role-playing games are about to take off in a big
way. Phil Garrett looks at part of what is on offer.
22 MEMORY MAP Exploration into Ihe memory map tan bring new joys From
your ZX 81.
27 16K RAM Sinclair's I8K RAM opened up a whale new world to users.
Stephen Adams looks nt ilscapabililies.
31 EIGHT PAGES OF PROGRAMS Let your fingers do the work Key-In our
great selections of programs. There is one I here for ZX-aoowners.
42TRIGGY QUESTIONS Have you ever wondered what SIN, COS ami I A\
on your keyboard do? We present a simple guide.
4ft MACHINE CODE Moving Oil from Basic:? Then this is Ihe series of articles
lor which yon have been wailing machine code explained in simple English,
50 STARTING FROM SCRATCH If you have just bought V° ur ZX-A1, don't
panic — read our guide to help you understand the system quickly.
53 INSIDE SINCLAIR Writer Lynd Church and photographer William Scolding
take I he hi nil road, this lime to Dundee, to find how the ZX-81 is manufactured
57 BUSINESS Mike Salem continues his series explaining why ihe ZX-81 can
be osed I o do some busi ness app] ical ions
fifl COMPETITION Don! miss the chance lo win a Sinclair printer in part two
of our competition.
61 BOOKS Publishers and authors are still producing books galore on the Sin-
ulair machine. We read another selection.
65 MIND GAMES This month Philip |oy gets lo grips wilh noughts and
crosses.
65 ADVERTISEMENT INDEX Due lo popular dnmand, we have started lo
mcl nde an index lo help ynu find the advertisements you specif ically wanl.
NEXT MONTH
• The ZX-Spectrum analysed in depth
• Who is THE WINNER OF OUR
FIRST COMPETITION?
• An indepth look at graphics software
ZX 80/81 HARDWARE/SOFTWARE
ZX KEYBOARD
Now with repeat kev facilities to add a numeric pad.
The keyboard has ail the 80/81 functions on the
keys, and will greatly increase your programming
speed. It is fitted with push type keys as in larger
computers
The keyboard has been specially designed for the
Sinclair computer and is supplied ready-built. It also
has facilities for 4 extra buttons which could be used
for on/off switch, reset, etc, £27,95. Numeric Pad
£10.00,
4K GRAPHICS ROM
The dK Graphic module is our latest 2X81 accessory. This module, unlike most other accessories fits
neatly inside your computer under the keyboard, The module comes ready built, fully tested and
complete with a 4K graphic ROM. This will give you 448 extra pre-programmed graphics, your normal
graphic set contains 64, This means that you now have 512 graphics and with there inverse 1 024. This
now turns the 81 into a very powerful computer, with a graphic set rarely found on larger more
expensive machines. In the ROM are lower case letters, bombs, bullets, rockets, tanks, a complete set
of invaders graphics and that only accounts for about 50 of them, there are still about 400 left (that may
give you an idea as to the scope of the new ROM). However, the module does not finish there; it also has
a spare holder on the board which will accept a further 4K of ROM/RAM. This can be used with a 1 K or
2K RAM chip for user definable graphics, so you can create your own custom character sets. £29, 95,
MEMORY 80/81
16K RAM
Massive add-on memory for 80/81 £32.95.
2K&4K RAM
Static Ram memory expansion for the 80/81 They both work with onboard Ram i,e, 4K plus onboard =
5K. This is the cheapest small memory expansion available anywhere. 2K RAM £14.95. 4K RAM
£19.95.
16K81 SOFTWARE
DEF LEX, This totally new and very addictive game, which was highly acclaimed at the Microfair, uses
fast moving graphics to provide a challenge requiring not only quick reaction, but also clever thinking.
Qneandtwoplayerversionson samecassette, £3.95.
3D/3D LABYRINTH. You have all seen 3D Labyrinth games, but this goes one stage beyond; you must
manoeuvre within a cubic maze and contend with corridors which may go left/right/up/down. Full
size 3D graphical representation, £3.95.
CENTIPEDE This is the first implementation of the popular arcade game on any micro anywhere. Never
mind your invaders, etc., this is positively shining, the speed at which this runs makes ZX invaders look
like agameof simple snap, £4-95.
16K GRAPHIC ROM SOFTWARE
CENTI PEDE Graphic ROM version of our popular centipede game,
SPACE INVADERS. The only real version of space invaders on the ZX computer.
Please add £1 p&p for all hardware, Software p& pf ree. Specify ZX80/8 1 on order.
ALL OUR PRODUCTS ARE COVERED BY A MONEY BACK GUARANTEE
dftronics
23 Sussex Road, Gorleston,
Great Yarmouth. Norfolk,
Telephone: Ya rmouth (0493 ) 602453
Su
SINCLAIR USER Maylfi82
sinclairvoyance
x.
\
ZX- 82 will be around soon
No other personal computer has had the sales
that the ZX-fll has had — and none has come
close. The sales of the pocket-book sized
computer are rapidly approaching 400.000.
Looking back to last month's Sinclairrayance, we
speculated about the arrival of the ZX-82 com-
puter. A machine with a better specification than
the BBC Micro, and built by Clive Sinclair, is
enough to whet any Sinclair user's appetite,
The ZX-82 is coming very soon! Many
potential ZX-81 owners are put off this marvel-
lous little computer by the fact that it does not
have a full-size keyboard or colour graphics or
sound output. The Spectrum, as the ZX-82 is
likely to be called, will have all these featu res plus
more. With its own matching ZX Microfloppy,
and retailing for approximately £140, this unit will
be available through mail-order only, until a suit-
able distributor can be found. The new computer
is Hkelv to have 32 K RAM fitted as standard.
The ZX-81 succeeded the ZX-80 in February
1981 when the ZX-80 users found that the
machine was not quite powerful enough. The
ZX-80 owners upgraded to the ZX-B1 specifica-
tion by inserting a new 8K ROM with floating-
point arithmetic, to replace the old integer-only
4K ROM, Unfortunately, ZX-81 owners will not
be so lucky — it will not be possible to interface
the ZX Microfloppy to the ZX-81, and there are
going to be no new ROMs for the ZX-80 or "81 ,
This is because of the technical difficulties of try-
ing to get the other features of the ZX-82 on the
ZX-81.
The Prestel adaptor which was due to be
launched at the Computer Fair will have to be one
of two possible types. It will either use the
ZX^Bl 's own 32 x 24 black and white screen for its
output, or it will have a standard 40 x 25 teletext
format. If it has the former, it will only be able to
pick up TeJsoflwore, whereas if it has the latter, it
would also be able to pick up Prestel pages of
information,
What I am leading up to, is that if the ZX-82 's
ROM could be copied and used in conjunction
with suitable colour Prestel adaptor, it might be
possible to implement some of the ZX-82's capa-
bility on the ZX^Bl.
When the BBC computer was announced, Clive
Sinclair said that he could meet the specification
laid down for about half the price. It now appears
as though he has done it A working prototype of
the ZX Microfloppy is due for completion about
now, and it will probably be very soon that
more details of the ZX-Q2 will appear. Mean-
while, work is still continuing between ICL and
Sinclair Research on the new digital terminal
using Sinclair's flat-screen technology.
One thing that is certain about the ZX-82 is that
it will use a similar language to the ZX-81 . Back in
December, Clive Sinclair was quoted as saying
"... we believe our language (Sinclair Basic)
now merits serious consideration ... as the
'standard' . . . ". Does it use the same cassette
format? Can 1 use my ZX-81 add-ons with the
ZX-82?
Only one man knows the answers to these
questions, and he is keeping his mouth firmly
shut at the moment,
Lets now look into our crystal ball to see if
Clive has anything planned on the software front.
Clive at one time sold his software in Smiths
but because of a 'high proportion of returns'
Smiths did not re-stock after Christmas. That
rebuff certainly stung Clive, as he is as aware as
anyone that there is gold in that-there software.
There seem to be two main options open to
him, Either to develop the software within his
organisation or 'get into bed with' an established
software company. He does not appear to have
the resources available to develop his own
software and a thorough examination of our
crystal ball shows Clive in deep conversation
with more than one software company and that a
deal could be imminent for new ZX software.
There are. however, two stumbling blocks. One
is the name under which the product would be
marketed. Respected companies which have
been or are about to be given the Smiths seal of
approval would want to cash-in on their success
and continue to market under their own names.
Clive would probably want the products to carry
only the Sinclair tag.
Second, the software companies might well be
afraid that Sinclair has once and for all blotted his
copybook with Smiths as a result of his not -very-
successful first attempt, thereby preventing any
chance of rich pickings in the high-street stores.
Neither of those problems is insurmountable,
however, so we would not be in the least sur-
prised if we hear an announcement from Clive in
the not -too-distant future that he is to start selling
some new software.
SINCLAIR USER May 1932
LEADERS IV COMPUTER GAMES
FIRST CHOICE FOR ZX : SUPPORT :
ZX-81
ZX-80
QS DEFENDER.
UP- DOWN THRUST -FIRE
First and only full screen display.
Software to drive QS SOUND BD.
Moving Planetaiy surface Up to
84 fast moving characters on
screen at once. On screen scoring.
Ten missiles at once. Increasing
attacK patterns. Requires 8K
ROM, and 4K mm of RAM AS. SO.
QS SOUND BD,
A programmable sound effects
hoard using the AY-3-9910. 3
TONES; 1 NOISE; ENVELOPE
SHAPER: * TWO 8 BIT I/O PORTS.
Easily programmable from
BASIC, the AY chip does most of
the work leaving your computer
free for other things. Signal O/P
via 3.6 mm Jack socket Porta O/P
via a 16 pin LC, Socket. *£fi.oo.
QSCHBSBD., 1
A programmable character
generator giving - 1£8 SEP-
ARATELY PROGRAMMABLE
CHARACTERS. OK/OFF SWITCH.
IKON BOARD RAM. Enables
creation and display of your own
characters to screen Dr printer.
Demo cassette of fast machine
code operation routines and lower
case alphabet included, See below
for ZX PRINTER listing 426.00.
Q5 - lower case
ft\
. ""'
*&6
'4?
v
QS OTVADERB.
LEFT - RIGHT FIRE
13*7 INVADERS, High score; 3
levels of play ; RND saucers; Bonus
base; Drives Sound bd . Gf CHRS bd _
Requires 7KRAM.BK ROM + Slow.
A8.S0.
QSHIRESBD.
A Hi -res graphics board giving
356 * 19S PIXELS- 6K ON BD.
RAM. SOFTWARE SELECT/
DESELECT. MIXED TEXT AND
GRAPHICS. 2K ON BOARD ROM.
Resident fast machine code
graphics software ( in ROM )
provides the following HI-RES
Commands. MOVE x, y; PLOT x,
T, DRAWx,y: BOX x,y; UP; DOWN;
LEFT; RIGHT; PRINT AS; SCROLL;
BLACK; WHITE CLEAR COPY. See
side for ZX PRINTER listings
using COPY. ASSOC
*Q ?
*^.' j
iA
x>
<* *
QS ASTEROIDS
LEFT RIQHT - THRUST FIRE
Software to drive QS SOUND BD.
Multiple missiles firing In 8
directions- On screen scoring
Increasing number of asteroids.
Fi.sH m ob 11 ltyof ship to all areas Df
the screen Two asteroid sizes.
Bonus ship at 10,000 points
Requires SK ROM, 4K mm of RAM
+ SLOW function AS. SO.
QSSXRANSd.
An extremely rehable static RAM
Bd. which combines with the
computer's memory to give 4K
total . Plugs direct in to the rear
port on your ZX Computer
Altt.OO.
QS MOTHER BOARD BD, & QS
COWTJECTOR
A reliable expansion system
allowing a total of any RAM pack
plus two other plug in boards to be
in use at once. On board BV
regulator drives all external
boards. Fitted with two 23 way
double sided edge connectors.
Connector is 2 * 23 way edge
conns soldered back to back.
Expansion can operate in two
ways ( 1 ) COMPUTER * *
CQNNE CTOR — * Any QS add on bd
( but no extra RAM pack). (2)
COMPUTER -^CONNECTOR -.
MOTHER BD — * ANY RAM PACK
( 2 bds to fit in mother bd. > Mother
board Al&.OO Connector A4.00.
Special offers & news
C 1 > U_3 Mother bd. -*- connector + CHRS bd + The special Graphics version of
ARCTIC COKPUTmCS EX CHESS 1 1 . A4B.00,
The strongest chess program with 7 levels of play.
C») QS MOTHER BD+CONNECTOR-HaUher SOUND or CHRS bd. A40.00.
We will be at the following shows . . . Come and see us . . .
THE COMPUTER FALR, Earls Court, 33rd to S 8 th April
3rd ZX MICROFAHl, Central Hall, Westminster.
30th April & 1st May
ii n
ALL PRODUCTS FTTLLT (HJARAWTEED.
QUICKSILVA: 9S, UPPBR BROWVHILL RD, ; MAYRUSH i SOTON | HANTS | EWGLAWD
Please state Type of machine, Which ROM, Memory siae, when ordering.
SINCLAIR USER hfnymz
hardware
world
To save
programming
time
A PIECE of hardware not
intended to fit on to the
ZX-61. Print 'N N Plot Jotter
is a pad of paper which
consists of two grids, one
for plotting Pixel graphics
and one for printing Alpha-
numeric characters- They
are intended for the pro-
grammer who wants to
improve his programs and
save time by planning his
displays on the screen
before PRINT AT X: Y:
ALPHANUMERIC or
PLOTX;Yapixel.
The Print W Plot Jotter
is also useful to use with
the Sinclair printer, as was
shown at the ZX Microfair.
by the firm producing an
aeroplane plotted on paper
more than one foot long. A
polyester film version is
also available for transfer-
ring book or magazine pic-
tures to the 2X^91.
The Print "W Plotter
Jotter costs £3.50 for 100
sheets and the film £2.25,
Both are available from
Butler Currie and Hook. 19
Borough High Street.
London SEl 9SE.
Keyboard
with a
difference
HAVEN HARDWARE has
gone one step further than
producing a real keyboard
and produced a circuit
which will make any key
on the keyboard repeat
after one second. It will
allow you to cursor right a
number of times, beck to a
mistake made in a INPUT
line, by holding-down two
keys. It is available on the
printed circuit board for
the Haven keyboard or can
From black boxes to boards . . .
to-the-point assessments of
hardware now on the market
ie attached to another key-
board by soldering it to the
ZX-80 or ZX-81 .
The keyboard module
costs £2.50 as a kit for
another keyboard or £2.50
for the components to
mount on to the Haven
keyboard.
Haven Hardware is at 4
Asby Road, Asby, Work-
ington, Cumbria C4 14
4RR.
Resolution
rise for
good graphics
QLHCKSILVA has pro-
duced a high-resolution
graphics board which will
produce BBC-type plotting
of lines, boxes and other
dot graphics. The ZX-80
and ZX4H chunky
graphics' with a maximum
a
T
-h
:x^>*fc2f
High-ma gmphius
resolution of 43 x 64 pixels
is replaced by a screen
offering a resolution of 192
x25t>
Each dot on the screen
can be addressed by an X/Y
coordinate in a REM state-
ment, which may have
mure than one command in
it. All the USR routines are
stored in a 2K ROM
mounted on the board, so
no machine code REMs are
required.
Drawing lines, boxes, or
only dots can be done in
either black Or white,
while clearing the screen
requires writing-over the
dots with the background
colour. Alphanumeric
characters can be used and
there are commands to
clear the screen in black
or white.
The board costs £85
inclusive and Quicksilva is
at 95 Hrownhill Road,
Maybush, Southampton.
FIZ into
floppy
action
CALLED a FIZ— Floppy-
disc Interface for the ZX-
81 — the Macronics floppy
disc provides a standard
5sin, floppy disc drive,
software in a 2K ROM and
a motherboard in the same
unit.
The disc will provide
43 K of storage which can
be LOADed at a rate of «K
in 22 seconds. The disc has
34 tracks and 10-128 byte
records on each track, for
storing data or programs
The commands are given
to routines stored in ROM,
so that no RAM is wasted
and all the disc commands
are written lobe used from
Sinclair Basic.
The motherboard pro-
vides all the power for the
system, including ZXnBi.
and interface cards to a
paper printer will be avail-
able soon. There is also the
possibility of a networking
card soon.
FIZ costs £303.03 inclu-
sive and is available from
Macronics, 2G Spiers Close,
Knowle, Solihull. West
Midlands 803 9ES.
Cheaper
printer
paper
IF YOU run out of paper,
whal do you do? Do you
panic and send next time
for twice as much as you
need from Sinclair? Now
there is an alternative
supply which should be
quicker and cheaper than
Sinclair.
Silicon Tricks can
supply five rolls of elec-
trostatic paper, the same
size as Sinclair paper, of
similar quality. The price
for the five rolls is £7.50,
whereas the Sinclair cost is
£11.95. Ten rolls cost even
less per roll, at £14.50 They
are available by mail urii«r
only. Silicon Triuks, 2-4
Chichester Rents, Chan-
cery Lane, London WC2
IE]. 01 -603 6074.
Building
memory
by blocks
A RAM extension kit is
expandable in the form of
2K blocks up to a maxi-
mum of 16K, as and when
you need il. H requires itu
soldering connections and
fits in the ZX-81 beneath
the keyboard.
If you later decide to buy
an external 18K pack, the
internal RAM can be
altered to fit into the next
ltiK section, so that you can
have continuous Basic
memory up to a total of
32K.
[continued on page 8}
re*
SINCLAIR USER Muylfl82
W
/continued from page 7\
There ere two kits avail-
able. 2-flK RAM costing
£8,50 and 2-1 BK at £9.50.
Details are available from
East London Robotics
[Electronics), Finlandia
House. 14 D&rwell Close,
East Ham. London E6 4BT.
01-471 330H.
Artie
comes in
with Forth
FORTH, the language in
which you can build a
vocabulary of your own
commands. can now
replace Basic on your
ZX^Sl. This version of
Forth resides in EPROM
like the Sinclair Basic and
is therefore available when
switching -on the power,
with no LOADing
problems.
Forth programmers
write the commands in trm
form of subroutines, which
are then COMPILED into
machine code.' so that they
run faster than their Basic
equivalent.
Forth is available from
Artie Computing, 396
fames Reckett Avenue,
Hull, North Humberside
HU8 0JA,
The joy
of real
joysticks
THERE ARE now proper
joysticks with a smooth
action and fire button, like
the expensive computer
games machines, available
for the ZX-fll. The joystick
is attached to the ZX-fll via
a controller board which
plugs into the hack of the
ZX-61 and has a connector
on the back for the 16K
RAM pack printer.
The joysticks are used by
selecting the movement to
High quality joysticks
be tested UP/DOWN,
LEFT/ RIGHT and then
using the PEEK command
to see the position of the
joystick, That can give a
result between 27 and 114
but it can be altered on the
board.
All the instructions can
be in Basic or machine
code and the cost of the
joysticks is £9.60 each,
with the controller board
costing £129.80. Space
In voders and a Maze geme
are already available from
Micro-Gen. 24 Agar Cres-
cent, Bracknell Berkshire.
0344-27317-
Experiment
with blank
boards
BLANK printed circuit
boards are now available
for experimenting with the
expansion bus or mother-
hoard of ZX machines.
They have a gold-plated
edge connector on them, in
which only a slot for the
keyway needs to be cut. As
they are coated on both
sides in copper, you can
design your own circuit to
use the ZX-fll as a con-
troller of devices and then
etch away the copper at
home.
That leads the way to
even more products for the
ZX machines, as the cost
of making experimental
boards falls.
Cambion Electronics
produces the board for £3
and ten be reached at
Castleton, Sheffield S30
2WR.
As easy
as drawing
on paper
THE LATEST device from
RD Laboratories for its
8100 system is a light pen
which, when used with the
slow mode of the ZX-fll.
can impact with the pro-
gram on the screen. That
means that drawing pic-
tures on the screen, using
alphanumeric characters,
or plotting using pixels is
as easy as drawing them on
a piece of paper.
it can also be used to
select from a menu of
items, as in a multiple-
choice question, without
making a mistake by push-
ing the wrong button. All
that can take place using
Basic or machine code.
The light pen system
consists of a Micro-Mum
(RD8100) motherboard,
light pen and access unit
(RD8180), plus a Free
demonstration tape of soft-
ware. The cost is £49.50
from RD Laboratories, 5
Kennedy Road, Dane End,
Ware, Herts SG12 OLD,
09 20-843 BO. It is one of the
many modules available
for the system.
Redditch
sticks with
Sinclair
REDDITCH Electronics
will supply everything
from a ZX -BO/81 edge con-
nector to a programmable
timer-counter oscillator
on one board. It can also
supply motherboards, key-
boards, A/D and D/A con-
verters and power
supplies, as well as books.
The boards are available in
kit or ready-built form.
The firm knows Sinclair
Research equipment well,
as it was one of the few
which supported the first
Sinclair effort in comput-
ing, the MK-14, long after
Sinclair had abandoned it.
Redditch Electronics is
at 21 Ferney Hill Avenue,
Redditch. Worcs B97 4RLL
0527-61240 — 0900-1230.
1400-1 700 hours.
Plugs into
the edge
connector
A BLACK BOX which
plugs into the edge connec-
tor of the ZX-BO or ZX-81
giving 5 K of Basic memory
and an inpul/uulpul sort is
known as the V pack, the
basis of the DCP system. It
is accessible from Basic via
the PEEK and POKE com-
mands, and the port is
memory-mapped.
The input/output section
can be attached to two
other modules, one at a
time, tu give A/D-D'A con-
version or larger current-
handling capacity via
replays. The D/A pack is
known as the 'A' pack and
the relay as the "C pack.
The price of the P' pack is
£37.95. "A' pack rusts
£19.95 and 'C pack £29,95,
They are all enclosed in
tough black boxes and, like
the 'P h pack, contain
instructions for use with
other circuits. A speech
talker will soon be
available.
DCP is at 2 Station Road,
Lingwood, Norwich. Nor-
folk N13 4 AX. 0603-7 12482.
SINCLAIR USER Muy 1882
Memotecfrs New Memoiy S ystem for the ZX81
It grows as youprogress
Memopak 18K Memory Extension
- £39.95 uiciMT
It is a feci that the ZX81 has revolutionised home computing,
and coupled with the new Memopak t6K it gives you a
massive 1 6K ol Directly Addressable RAM. which is neither
switched nor paged With the additkOn of the Memopak tGK
your ZX91 s enlarged memory capacity vnll enable it to
execute longer and more sophisticated programs and lo
hold an extended database
The 16K and 64K Memopaks come in attractive, custom-
designed and engineered cases which lit snugly on to the
back of the ZXB* giving firm, wobble- tree connections
See be*ow for ordering information
MEMOPAK RAM
HI -HE S GRAPHICS
CENTRONICS if.
Coming Soon.
Centnjnici IrflEriacF «Xt 5fl*tWW» Dnwri
i Diqrhiing TaCta* f*5?3J mtqrt ace
All these products are designed to fit 'piggy-back' fashion
m to eacn other, and use the Sinclair power supply
WATCH THIS SPACE for further details. We regret we are as yet
unable to accept orders or enquiries concerning these products
- but well set you know as soon as they become available.
How to order your Memopak.
By Post: Fn -n the coupon below and enclose your
cheque/P.O,' Access or Bardaycard number
By Phone: Access'Barclaycard holders please ring
Oxford (0865) 722102 (24-houf answering service).
Memopak 64K Memory Extension
-*7ft00incLVKr
The 64 K Memopak is a pack which extends the memory ot
the ZX81 by a further 56K. and together with theZXBI gives a
full 64K, which is neither switched nor paged, and is directly
addressable. The unit is user transparent and accepts baste
commands such as 10 DIM A('90O0)
BREAKDOWN OF MEMORY AREAS
Q-QK . . Sinclair BOM
8-16K . This section of memory switches in or out m 4K
btocks to leave space for memory mapping holds its
contents durmg cassette loads, allows communication
between programmes, and can be used to run assembly
language routines
T6-32K . . . This area can be used for basic programmes and
assembly language routines
32-64 K . . 32K of RAM memory lor base variables and large
arrays
Wrth the Memopak 64 K extension the ZX8 1 is transformed mto a
powerful computer suitable for business, leisure and
educational use. at a fraction of the cost of comparable
systems
Unique 3 month trade -in offer!
When your programming needs have outgrown the capacity
provided by 16K RAM. and you find it necessary to lurrher
extend your 2X81 's capacity we will take back your 1 6K
Memopak and allow a discount ol E t 5.00 against your
purchase of our 64K model.*
'We reserve the tight to refect, for discounting purDos&S. units w '
have been either opened or damaged m any way
<
o
£
CO
DC
Please make cheques payable to Memotech Limited
Please debit my Access. Bardaycard* account number
Please send me:
ZJ
' fltease d&efe A+icfiener ctoes not apply
SIGNATURE ,
I
I NAME.
I
I
.DATE
Quantity
Price
Total
I6K RAM. Assembled
£39.95
64K RAM, Assembled
£79:00
Postage
£2.00
Total Enclosed
1RFRS
m
We want to be sure you are satisfied with your Menwpak - so we offer a 14-day money back Guarantee on all our products.
Memotech Limited, 3 Collins Street, Oxford OX4 1XL, England Telephone: Oxford (0865) 722102/3W5
"THE BEST ZX81 BOOK
ti
THE
ZX81
COMPANION
Bob Maunder
LINSAC
ISBN090721 1 01
If you have a Sinclair ZX8 1 and want to use il lo its fuH potential
t he n , a s ih e experts have all ag reed, t his is th e boo k f o r you. 1 1
contains detailed guidelines end documented programs in the
areas of gaming, information retrieval and education, as well as a
unique listing of the SK ROM lormacrnne code applications
'Far and away the best , . once again Lmsac has produced the
boo k for the serious end of the market'.- Your Computer.
November t$S1 ,
TheZXBl Companion is a most professional product with many
good illustrative programs, lips and warnings'. -Education
Equipment, October 198 1
'Bob Maunder' s attempt to show meaningful uses of the
machine is brilliantly successful thoughtfully written, detailed
and illustrated with meaningful programs . . . To conclude -the
book is definitely an outstandingly useful second step for the ZXB1
user' . - Educational ZX80/8 1 Us ers ' Group Newsletter. September
WB1
Send your cheque for f 7.95 (includes UK p&p) to
Price El 95
LINSAC (SU)
68 Barker Road, Lmthorpe,
Middlesbrough TS5 5ES.
Music
IK
£2.95
Music ?-
-16K
1 1 M
N iq him are Park
IN
£4 %
High Has. Graphics
16K
£3 95
Space IrWldSrs
IK
£4 95
Space Invaders tut
JK
£5 95
Breakout ia i ■
Ik
£3 45
Dragon Mare
16K
£4 95
Planetoids
16K
£3 95
&Cr*ll
nailing Rriir 1
- 16K
£7 95
Lft)
1bK
£3 95
Statue*
1BK
£4 95
Mission b!
the Peep
1SK
£5 95
Fruit Machine
and Ptnitftftn
Mi
£2 95
Space Rescue
1EK
«.S5
Warrior
1EK
E4 95
3D '"«" i 'X"i
+ Connect Four
INK
£5 95
ftisenihtv Hi ",,.„ ik C595
*ssembhj 13 .--..., 3K tB.as
Hex Mr/D. M« IK £1 0.0
-'•-- No hardware nMditicaiwns -, :
whatsoever
S.A.E. 'or catalogue
All urograms supplied on
cassette with instructions
Send remittance wtlh order
(Cheque. P.O. Card No.) toe
iii;m n;s
Ur.pl SU
26 Spnn Clo&e
KmhH
MM
Wesi Midlands B93 9E5
111
SINCLAIR USER Mupliez
software
scene
More software delights
for your machine
Making
maths
easier
A PROGRAM which
appears to defy the rules of
mathematics has been add-
ed to the Video Soft-
ware range of serious 1
software for the ZX-81,
Called Video-Index, the
maths-defying element is
the fitting of 57.000 charac-
ters of data in a l&K mem-
ory, which is achieved by
an ingenuous technique
whereby duplications of
descriptions are detected
and eliminated.
Written largely in mach-
ine code for speed, Video-
Index provides a technique
for using the ZX-81 to build
a catalogue or index which
can be stored on cassette
and re-used. The program,
which is supplied with a
demonstration index of
computer magazine arti-
cles about the ZX-81. costs
£9,95 and can be obtained
from Video Software,
Stone Lane, Kinver, Stour-
bridge, West Midlands
DY7BEQ.
Ten games
on one
cassette
A CASSETTE with 10
games to run on the ZX-81
with 16K RAM offers a
wide choice. Recorded on
both sides, the cassette,
offers all 10 games twice
but in a different order,
depending on the side of
the cassette used.
SINCLAIR USER MayW2
The games include
board and card games such
as Othello and Pontoon and
combat games such as
Loser Bases-
It also offers Rectangle,
where the object is to form
rectangles with a bigger
total area than those
formed by the computer.
The skill in this game is to
form rectangles which are
fairly big without having
them blocked and at the
same time to use your
points to block the rectan-
gles the computer tries to
make.
The user and the com-
puter take turns to choose a
point, neither knowing
which points the other has
chosen until one calls
'show'. The games, assem-
bled on the Cassette Two
which costs £5. are avail-
able from the Michael
Orwin ZX-81 Software
Catalogue, 26 Brownlow
Road. Willesden, London
NW109QL
Orwin is putting to-
gether Cassette Three,
which includes a game
called Princess of Krooi,
wherein the princess has to
be rescued from a dungeon
six levels deep and where
you, the rescuer, having
chosen the level of diffi-
culty, time period of the
game and type of maze,
find your way to the cor-
rect room via perils includ-
ing rockfalls. monsters and
floods. There are soitir
bonuses on the way but the
princess is undoubtedly
difficult to find>
Galaxians
invade
W H Smith
A VERSION of Galaxians.
the popular arcade game, is
now available to ZX-fll
users through W H Smith.
Called predictably ZX-
Goioxians. it requires 16K
of RAM and offers person-
alised high-scoring rou-
tines, swooping attackers,
full explosions and contin-
uous Stat Us reports.
The originators, Artie
Computing, believe lhat it
was chosen by W 1 1 Smith
because it is exceptional.
Written in machine code,
the game runs smoothly
with no flicker on the
screen, mostly because it
uses pixels which split the
characters in two.
W H Smith is selling
Galaxians on a cassette at
C4-95, which includes a
dungeons and dragons ran-
dom adventure game,
Swords of Peace. Artie
Computing can be contact-
ed al '19B James Reckitl
Avenue, Hull North
Humberside.
Helping
with
machine code
AN EFFECTIVE lool for
the speedy development of
Z-80 machine code rou-
tines entails a number of
procedures which will
facilitate loading, as well
as check and query errors-
Developed by Michael Cox
Information Services, the
M/C Load and M/C Edit
programs form a suite
which retails at £8.90 and
is intended for use with a
fully-debugged machine
code program
The procedures require
you to draft your routine
manually, listing Assem-
bler mnemonics and. for
the Instruction codes, the
relevant hex code. Using
M/C Load, you then enter
hex and decimal argu-
ments to derive the ZX-81
code, which is added to the
manual draft.
Using M/C Edit, the ZX-
81 code is entered together
with break-points as
required. So, when the
routine is proved, the M/C
Load program is used to
enter the finished routine
in memory.
Ccfjrrtiniffjd 1 on pagr \2\
11
i*oa
t-&0
[continued (rtim page 1 f 1J
MCIS t:an be contacted
at 62 High Road, North
Weald Basset I Essex
CM 16 6 BY.
Banking
on a new
system
A SYSTEM which enables
you to keep detailed
records of bank transac-
tions and thus produce a
better statement than that
of your bank can is avail-
able to users of the ZX-81
16K RAM system. Personal
Banking System offers faci-
lities such as automatic:
posting on the statements
of all standing orders due
monthly, quarterly, six-
monthjy or annually and
Ghbons 14 Avalin Road.
Orpington, Kent BR6 9AX.
incorporates a machine
code load/ save feature
which permits the storing
of transactions in data files
on cassette, separate from
the program. That facility
saves and loads the pro-
gram varibles only.
The Personal Banking
System is available for
£9.95 inclusive of cassette
and user manual from I P
Dangers
from a
starship
ANOTHER GAME for the
soon - to - be - released
Michael Orwin Cassette
Three requires 16K of
memory and will he one of
10 or so games on the cass-
ette. Slamhip Tro/un puts
you in the unfortunate
position of being the only
survivor on a starship
which has been badly
damaged In a meteor
storm. It is satisfactory to
be a survivor but you have
to repair the damage to the
ship before the total air
level drops below 3,000
units and you only have 70
hours for repairs before
your next inter stellar
jump.
There are other dangers
lurking but at least you are
armed with lasers and stun
grenades. The game pro-
mises to be at least as
absorbing as previous
Orwin cassettes and will
be available from Michael
Orwin, 2b Brownlow Road,
Willesden, London NWlf)
SQL.
ZX81 SOFTWARE FROM VIDEO SOFTWARE LTD 1K&16K
16K SOFTWARE
VIDEO-SKETCH [Z.XB1 only} Move the cursor to any
part of the screen. Draw or rub-out as you move it Mix in
text or graphics Save picture in memory. Save picture
sequence on cassette.
VIDEO-PLAN I.ZXS1 only) Performs the function of an
analysis book Arithmetic functions include addition,
subtraction, multiplication
VfDEQ-AD Rotating display of 1 6 pages of advertising
material. Set-up your own pages and change them as
and when required.
VIDEO-GRAPH. Planning and design aid. Create
pictures/cha rt a/graphs and Store within the program
VIDEO-VIEW. Do it yourself teletext. Create pages of
data Store them withrn the program.
VIDEO-MAP (2X81 only* Educational game based on
maps. Navigate your plane io its destination.
FORCE-FIELD [ZX81 only* Animated bombardment
game
SPACE-RACE (ZXS1 only) Party game for eight
players.
TEST-MATCH Realistic simulation of a lest match
series Dynamic scoreboard
FOOTBALL-LEAGUE. Realistic simulation of an entire
season. Every match played and results shown with
progressive league table.
STOCK-MARKET (ZX8 1 only, An exciting game of skill
and judgement. Buy and sell stocks and shares as prices
change in response to world events.
PACK1 -VIDEO-PtAN+VIDEO-AD
PACK 2- VIDEO-VIEW* VIDEO-GRAPH
G AM ESET- VI DEO' MAP + 5 GAMES
1 K PARTY TRICKS IZX81 only!
Personal ca
PRICE
7.95
795
7,95
£5.95
595
595
395
3.95
3.95
395
395
17.95
13 95
19 95
495
NEW
NEW VIDEO-INDEX
Q How do you store 57.000 characters in a 16K RAM
A. Use VIDEO-INDEX.
Catalogue your cassettes, your record collection, references to
magazine articles. Amazingly versatile. Capacity for 1 r 0OG
individual references each of which can generate 57 characters of
text, Powerful search facilities once the index has been ere a ted.
How is it done? The system cannot really fit 57,000 characters
in a tfjK RAM. It gives the illusion of doing so by eliminating
duplicates For instance in an index of articles m computer
magazines about the ZX81 certain words occur time and again
VIDEO-INDEX detects these duplications and thereby conserves
space.
Whatdoyou get 5
1 A machine code master program which sits at the top of RAM
This is initially loaded like a BASiC program.
2 A demonstration index containing 1,000 references to articles
about theZX81 in the popular magazines.
3 A detailed instruction manual.
You may then proceed to create your own catalogues and indexes
and save them on cassette
This program is fast, efficient and ingenious and is by far the best
product we have miroduced for theZXSI
N.B. There isn't room for a commentary on th*s cassette so you II
have to read the manual.
ZX81 orZXSO + BKROM
ZX printer is useful but notessential Price; E9.95
Mail Order Customers add El per order.
Allow 2 8 days for delivery.
Cash with order please to VIDEO SOFTWARE LTD
Stone Lane, Kinver,
Stourbridge.
Hers welcome during office hours. West Midlands DY7 6EQ
\l
SINCLAfR USER MaylMBi
MORE FUN WITH YOUR ZX81!
& AC K
The addition of our fully-compatible,
assembled, tested and guaranteed
16K RAM PACK
PUSH-ON PLUG-COMPATIBLE MEMORY
Means more memory for better games
and bigger programs
ORDER YOURS TODAY FROM:
CAPS LTD. Dept. F, 28 The Spain, Petersfield, Hants GU32 3LA
Please send me my Byg Byte 16K Ram Pack. I enclose cheque/
postal order tor £34.95 (includes VAT, Postage & Packing)
Name ..
Address
Dept. F
A flow 28 days for delivery
Fully inclusive price
£34.95
SINCLAIR UiitR May 1382
13
7??
I HAVE had many letters in recent
weeks asking about the methods
used by the ZX-B1 to store and
display numbers and so i have
devoted this month's column to the
topic.
The machine uses one of three
methods, depending on the context.
The first is the floating point method
which is used for all Basic variables
and all calculations involving Basic
variables. All numbers held using
the technique occupy five bytes
each. The second method is used
internally by the Z-&Q micropro-
cessor which drives the ZX-61 and
canbe used for whole numbers only.
Each number occupies only two
bytes and a variation of the method
is used to store the line numbers at
the beginning of each Basic program
line. To communicate to the user the
ZX-61 uses a third method, the
character form, in which each
decimal digit, and the decimal point,
occupies one byte each. All the ques-
tions this month concern the floating
point method. The first is from James
Tucker of Solihull , who asks;
What does floating point
arithmetic mean? Why use it?
Would it not be easier to use the
decimal system?
The use of floating point arith-
metic implies that numbers are
stored and manipulated as a
mantissa, which contains the digits
in the number, and an exponent,
which indicates the position of the
decimal point. It is relatively easy to
convert decimal numbers into a
decimal floating point representa-
tion and some calculators can dis-
play decimal numbers in that form.
The calculator manufacturers refer
to the form as scientific nutation.
The great advantage of scientific
notation is that very large numbers,
or numbers which are very close to
zero, can be written approximately
using a limited number of digits.
Thus a calculator which can display
only eight digits at a lime can display
a number larger than 99.999.999
using scientific instead of ordinary
notation.
For example, the distance from the
earth to the sun is about
5,892,480,000,000 inches. Thirteen
14
digits are required to write the
number in ordinary notation but
when it is re-written in its scientific
form hs 5.69248 x 10 u only eight
digits are required — neglecting the x
10 which is common to all numbers
written in that way. The mantissa is
589248 and the exponent is 12 r
The exponent, by the way, means
"imagine that the decimal point is to
the right of the left-most digit of the
mantissa — i.e., between the 5 and the
8, Now move the point 12 places to
the right, filling spaces with zeros if
necessary".
The scientific form, of course, is
not accurate because only eight
digits, of which six only are in the
mantissa, are allowed, whereas in
the ordinary form 13 are available,
although in our example the extra
digits are all zeros.
We count in tens and so calcula-
tors display numbers in decimal for
our convenience. Digital computers
count in binary as explained in
chapter 24 of the ZX-8I Basic pro-
gramming manual but the principle
of floating point binary representa-
tion is the same as that of decimal
scientific notation. TheZX-81 uses a
string of seven zeros and one for the
exponent — i.e., one byte with one bit
reserved for the sign of the expon-
ent — and a string of 31 zeros and
ones for the mantissa— four bytes
with one bit used for the sign of the
mantissa.
Floating point arithmetic is used
because it enables a large range of
numbers to be stored in five bytes
with only a small loss in accuracy.
Andrew Hewson
%ur queries
numbers ans
In this column Andrew
Hewson, author of Hints &
Tips for the ZX-80 and Hints &
Tips for the ZX-81, answers
your questions on hardware
and software for Sinclair ZX
Numbers as big as 10* — one
followed by 36 zeros — can be stored,
although only the first nine digits or
so are accurate. If integer arithmetic
were used, then the biggest number
which could be stored in the same
Space won Id be 1 ,099,51 1 .627,778 fall
all ] 3 digits would be accurate.
How are numbers stored in the
ZX-81? Please explain how the
five-byte representation of a
number is obtained, writes Peter
Stern of London.
The following program prints the
floating point form of a number
entered by the user at line 20:
10 PRINT "ENTER A NUMBER"
20 INPUT I
30 PRINT. /THE ZX81
REPRESENTS": I :"BY"
40FORJ = lTO5
50 PRINT PEEK [PEEK 16400 + 256*
PEEK 16401 + 7]:"";
60 NEXT]
70 PRINT
60 PAUSE 300
90 CLS
100 RUN
SINCLAIR USER May i8B2
helpline
is on storing
lswered
w
fr
&■
rs
re
;x
computers. Please address
your problems, queries and
comments on the computers
to Andrew Hewson, Help-
line, 7 Grahame Close,
Blewbury,Oxon.
The ZX-81 stores the values of all
Basic variables in the variables areas
and the address of the beginning of
the variables area is held in VARS at
locations 16400 and 16401— see
chapter 28 of the ZX-Bl manual.
Thus the loop at lines 40 to BO prints
the contents of the five bytes which
hold the floating point version of the
number entered.
The first of the five bytes is the
exponent, E. and the remaining four
bytes. A, B, C. U represents the
mantissa. If the original number is
positive, A lies in the range to 127.
If it is negative, A lies between 12B
and 255.
The following program re-con -
tructs a number from its Sinclair
floating point form:
10 PRINT 'ENTER THE
EXPONENT AND THE FOUR
NUMBERS OF THE MANTISSA.
ALL ENTRIES TO LIE BETWEEN
AND 255 INCLUSIVE"
20 INPUT E
30 INPUT A
40 INPUT B
50 INPUT C
60 INPUT D
70 INPUT , ."EXPONENT* "
,E,"MANTISSA = " ,A„B„C.,D
80 PRINT , "THE NUMBER = "; [2*
IA< 12BHT*2**lE-lfiO)*(((25B*
( A+l 2B* [ A < 1 28)HB) *256+C)
*256+D]
Try those two programs for a
variety of numbers. You will see that
the exponent is about 128 for
numbers close to 1 and -I; that
numbers close to have small
exponents; and that large positive
and large negative numbers have
large exponents.
It is also noticeable that the value
of the fourth byte, D, has little or no
effect on the value printed by the
second program. In computer jargon
D is called the least significant byte.
The ZX-81 prints results to eight
decimal figures at most, rounding
the result if necessary, although
calculations are made to somewhat
greater accuracy.
The final question is from Roger
Hurr of Coventry. He writes: I am
writing a program to lest my son's
arithmetic but I have found thai my
ZX-81 sometimes gets the answer
wrong. 1 know that some early
ZX-81 ROMs made an eror with
the square of 0.25 hut my machinn
does not make that mistake. Is this
another bug?
He sent his program and il became
apparent quickly that the fault lay
with his program and not with his
ZX-81. The routine which was at
fault set a problem in division and
then compared the user's reply to the
result calculated by the ZX-81.
Unfortunately for him the routine
often rejected correct replies.
It is often impossible to convert a
decimal number exactly to a binary
floating point number and thai was
the source of Roger's problem. An
analogous difficulty can occur when
converting some fractions into deci-
mal—we are all familiar with the
fact that 3 cannot be written as an
exact decimal. The program was
rejecting the user's reply even when
it differed by only a tiny amount
from the calculated result.
The following program asks you
to enter a number, divide it by 10 and
enter the result. It then prints the
floating point representation of your
result and its own result for the same
calculation. If you run the program a
few times you will see that your
answer and the answer produced by
the ZX-81 often differ by one in the
least significant digit of the
mantissa.
10 LET N = 500
20 CLS
30 PRINT "ENTER A NUMBER"
40 INPUT I
50 PRINT , , "YOU ENTERED" :l
60 PRINT,. "DIVIDE";!; BY 10"
70 PRINT "ENTER THE RESULT"
80 INPUT J
90 PRINT , , "YOU ENTERED" ;J
100 LET K =1/10
110lFABS[K-J)<.OOOrKTHEN
GOT0 170
120 PRINT,," WRONG"
130 PRINT I: "DIVIDED BY 10 DOES
NOT EQUAL";]
140 PRINT 'TRY AGAIN"
150 PAUSE N
160 RUN
170 PRINT, ."RIGHT
180PRINTI;"/10 = ";J
1 90 PAUSE N
200 CLS
210 PRINT,. "THE ZX81
REPRESENTS" ;];"BY"
220 LET M = 13
230GOSUB300
240 PRINT , , "AND" ;]; '710 BY"
250 LET M= 10
26GGQSUB300
270 PAUSE N
280 RUN
300 FOR L = M TOM +4
310 PRINT PEEK (PEEK 16400 + 256
* PEEK 16401 +L);"":
320 NEXT L
330 PRINT
340 RETURN
If you wish to avoid problems of
that nature then you should alter
statements like
IFK = JTHENGOT0170
toIFABS[K-|)<0001*KTHEN
GOTO 170
In the first case the program will
jump to line 170 only if K and I are
identical down to the last digit. In the
second case, the jump will be made if
the difference between K and ] is
less than .01 percent.
©Copyright Hewson Consul tnnLs VHB2
SINCLAIR USliR MuylOBS
15
HVLDERBAY LTD PROFESSIONAL SOFTWARE
\
If you don't believe that the Sinclair ZX81 can do real work,
comeand see us at the Computer Fair Exhibition, Earfs Court
[23rd-25th April)snd f he IX Micro Fair, Central Hall ,
West minster, London SW1 (30th April -1st May),
ZX81&1GK SOFTWARE: Reviewed in "Your Computer" (Fee. 1962)
* Payroll for up to 30 employees. Meets all regulations E25.
* Stock Control Fast, big, and versatile £25,
* Budget £15.
* Critical Path Analysis Up to 500 activities £15
* VAT & Mortgage £ Loan £ 8 .
* GOLD: A really good adventure: together with the intriguing
'■PickaWord".E8.
* RELIABLE 16K RAM Pack for the ZX8 1 £42.
* BE AMSC A^ : Bea m a na lysis for architects an dengineersE2 5.
* APPLE 1! Payroll: £35
* HEWLETT PACK ARD9845B: Superspline (general purpose
interpolation and tabulation).
* M E MOT ECH 64 K Memopak £ 79
DOYOU HAVE DIFFICULTY LOADING TAPES! Wfehavethe answers;
and for well under £ 10
Contact u s for more deta i Is.
CROFTON PROFESSIONAL KEYBOARDS, MONITORS, VDUs
Prices include VAT. Post & Packing COD Orders £2 extra.
cOto
TAPE HINT: Don't use the first 20 seconds
of your cassettes — most tape problems
are found near the ends of thetape.
COMPETITION
WIN A
64KMEMOTECHI
Open load purdiasersol 'GOLD'
or Games Pack 1 ,
A 64K Meinotech will be sent to the
player wno sends us the highest
score received! by 31 July 1962,
Month ly prizes of b!a n k cassettes
for your programs!
II you tiave already bought ' GOLD ' ,
send sae for a copy of the rules
H-LDERBAYLTD198t
HILDERBAY LTD fYCMJ, 8/10 Parkway, Regents Park, London NW1 7 A A.
Telephone enquiries for Hilderbay Ltd, wilt now be handled by HOLDCO LTD.
Tel. 01-25 13090
ZX81&16K SOFTWARE
EQUATION PACK: linear and quadraticequations, sets, equationsof higher
degree. £8.
MATRIX ROUTINES : the matrix statements of normal basic (MAT . . r ) £8.
CALCULATOR PACK : theequivalent of RPN calculators. 40operationsand
functions. £8.
ELEMENTARY STATPACK : mean , variance, stand. dev, , stand.err,, covariance, corr.
coerf,anal. of variance, lin. regression £10.
METRIC/IMPERIAL/US CONVERSIONS : length, surface, volume, weights and
measures, speed £6.
TRIANGLES : completetrigs package £8.
POLYNOMIAL EVALUATION: operations, zero's (int. ,reaUomplex) and
Descartes £10.
BARCHARTS FOR ARCHITECTS : a simplified version , takesaway the tedious task of
manualiyhandlingthe problem £25.
BANK ACCOUNT calculate your bank charges whilst keeping your account £5,
HOLDCO GAMES — See our special advertisement in this magazine
Prices include VAT, Post & Packing COD Orders E2 extra.
HOLDCO LTD.
14, BRITTON STREET
LONDON EC1M5NQ
Tel: 01 -25 13090
16
SIMCLAIK USER MaylOM
letters
Filling a
market need
] FIRST heard of your
magazine at the ZX-
Microfair but I thought it
would just be two pages of
old news for members of a
user club. I am very
pleased to find it on
general distribution at
such a reasonable price.
The magazine seems to fill
a market need, judging by
the amount of ZX informa-
tion which has been
appearing in other
magazines.
I feel there are three
ways in which the maga-
zine could be improved.
First, the introduction of
an advertisers' index in an
easily-locatable part of the
magazine. Second, how
about having a small sec-
tion on the old MK-14
ranging from a piece about
what it was, to a regular
hardware and software
spot? Third, I find one of
the most informative parts
of computer magazines in
the letters page and 1 hope
you will introduce one.
The queries raised and
ideas suggested through
letters pages have often
prompted me to try ideas 1
would never otherwise
have thought of
Hoping that you will
maintain the same high
quality.
William Nuttal I
Lewes, E, Sussex,
•As you can see, points
one and three are now
taken care of. We are still
thinking about point two.
What do other readers
think?
Not just
propaganda
1 HOPE that in future you
will not merely publish
propaganda for Sinclair
Research, because
although the ZX-B1 is
undoubtedly an Rxcellent
machine, it has its faults,
and the Sinclair organisa-
tion still leaves something
to be desired.
An advertisers' index at
the back of the magazine
would be very hfilpful. I
wish you every success in
your new venture.
A. Maciure,
Wit ham, Essex.
♦See page 65 for the adver-
tisement index.
Monopoly
information
I EXPRESS my thanks for
the information relating to
ZX-B1 Monopoly.
We were pleasantly sur-
prised this morning to find
an order in our post for
it. As you are probably
aware, it is very unusual to
obtain direct response
from a press release,
especially so early after the
publishing date.
We wish you luck with
Sinclair User and enclose
information for your next
issue. We feel sure our
investment will be reward-
ed with an increase in turn-
over.
We would ask you if
possible to advise your
readers that ZX-fil
Monopoly requires 1GK
RAM to function- We esk it
because it was omitted
from your editorial and we
would rather not take
orders which eventually
will lead to disappoint-
ment for the purchaser.
Thank you for your
assistance and good luck.
Derek Tid man,
Work Force,
Luton, Beds*
Discipline and
guidance
ONLY a week after I
bought a ZX-81 and 16K
RAM, your welcome
magazine appeared in the
newsagents. Excellent tim-
ing, if] may say so.
It is obviously early days
for you but I hope that your
reviews of hardware and
software will be frank and
critical, as well as giving
praise where it is due. I
realise that as a commer-
cial enterprise you must
keep a weather eye on
advertising but the kind of
discipline you could help
impose can only be good
for products and users —
and for your circulation in
the long run.
I look forward to future
issues, and certainly wish
you well. Meanwhile I
wondered if you could give
Home guidance to help me
resolve a programming
problem?
To calculate hours
worked during a week
from data recorded on
time cards, thus;
Dale uippJLed
Mm Tub Wed Thu
Fri
il rr lHHI AUU Uft<M DWK
DM
dep. 1310 1232 1ZS& IZ42
1303
an. 140S U« 1315 139*
IS]
• 1 1<| i £705 I7tn IMA 17013
1054
To be adduced from d«1a
Total Total
4411
MM
HBO
MR
A 14830 B 1IJD4
A - B=:if.;»rJtourR worked, in hfiun ■hd
■ In al p
T. E.Newman,
Worcester Park, Surrey.
•Thanks for (he compli-
ments and we have sent
your problem to Andrew
Heivson, Hopefully he can
provide o solution- — Editor,
COUNTRY
PROFILE:
SHOPPING
BASKET
BUDGET DAY-
REFORM
OPPORTUNITY
'""THE LADY IS NOT FOR TURNING"
BUT ARE YOU?
Ever though t yoi i r:ui i Id m r 1 1 hs Cou in r v bener f H are is you r chance
You are PRIME MINISTER and CHANCELLOR OF THE EXCHEQUER of 'GREAT
BRITAIN You nave the upprtrinndy (n select ihe Parly you wish EQ represent
AiirJ t'aut A]M is io stay in Off its (or as ilono. bs puMihlj*. ydu will MowevHt need
pkn i y n1 skill and foresight il you a re t □ slay infer any length nf i™
You ntusl control INFLATION, keap down UNEMPLOYMENT, murium rrwi
EXCHANGE SATE, introduce SOCIAL REFORMS and try slay POPULAR wiln
the Elector ale
GAME SECTORS
Informauon about (tie Counity's popmlauon, number ol
Companies m. business, Ta* income. Exp*™"'!*"-* * nrJ Curranl
At i: tmnl ha in nctt will be available
Cnneni urines ol various prcducls. i* PETROL. SCOTCH.
MILK etc ni(jrirhnr the RPI and Average income liguras
will ba given
You must lry to balance four need for titr* income
against the need <G t urn rol I N F LAT ION and U N EM PLOY M E NT
ate. You have (he Opportunity is make changes 10 ihe various
TAX RATES and BENEFITS: lhe data obtain*! from Ihe
Profile arvd Shopping Basket should be ustrful to you <n Ihe
prepjirjilir'in at yam BUDGET
iTiirnduiie SOCIAL REFORMS end make
your jell POPULAR taitk your reforms wisely and waii-h vuur
spending!
AT THE END OF EACH YEAR THE COMPUTER WILL PROCESS THE DATA
INPUT DURING THE PERIOD A NO WILL AOJUST THE MAJOR INDICATORS
ACCORDINGLY (A TELLING TlME'l
>n your 5 lh year a G E N E R AL ELECTION m usf take place
ELECTION Results will cpme in during lha mgnl and the SEAT TOTALS
NIG NT: for each pt (he Pome* will be incremented accordingly If you
have a suffloieni maiorny you will OS asked to continue in
Office lor a lurthar TERM
You m*v *iih#r eontmua immedialely. SAVE Id Up* 10
conlinue latPiT^r mtiifl exhausted.
IF YOU ACHIEVE MORE THAN 5 TERMS I WOULD BE INTERESTED TO HEAR
HQW YOU DID IT.
The Game n called GREAT BRITAIN LIMITED" and is available on tassetievmh
detailed Instruction* ai only C4.95 Irom
-.wn* SIMON WMESSEL Dapt.S.
7X8 l 15. kYTHAM COURT. CARDWELL
CRESCENT SUNTJINGHlLL BERKSHIRE
Fast Efficient Service - Details ol other games on request Is** last month's S U re
INHERITANCE "I. Full Montry-Back Guarantee
16K
RAM
SINCLAIR USER May 1982
I?
Watch out for
Phil Garrett tries to guide you through the world of adventure
games in this the first of two fascinating articles on the subject
IF YOU enjoy delving into rat-
infested dungeons, crawling
through dimly-lit caves, and
wandering round long-abandoned
mine-workingSt Adventure is for
you. Your powers of memory, logic
and patience are tested to the limit as
you lake life-and-dealh decisions in
your search for fame and richf^ — all
without leaving the comfort of your
chair and with only one risk to your
physical well-being. That is a severe
headache after bashing your head
against the wall then your latest
seven-minute Adventure failed to
load for the fifth time.
Adventure is a role-playing game,
where after being told about your
immediate environment, you can
enter commands such as "Go west",
"Take keys", "Throw knife". The
computer will then provide an
appropriate response, such as a new
room description. "You missed", or
some other message. You many
encounter fabulous treasures, or
perhaps only mundane objects,
although they may, jf used correctly,
be the key to a still greater fortune.
You will probably need to make a
map as you proceed to have some
chance of re-tracing your steps to the
entrance, Natural — and unnatural
— hazards abound to prevent your
escape, and it should take many
delvings to discover all that an
Advenl ure contains.
Computer Adventures are e
surprisingly recent invention, the
original having been written on a
mainframe in 1976 by William
Crowlher and Don Woods at
Stanford University in the U.S. It is a
remarkable achievement when you
consider that, until recently, Fortran.
the language they used, had none of
the string- handling facilities of
Basic. Until two years ago. Adven-
ture was strictly the preserve of
computer professionals but the
growth of micros has resulted in far
wider use.
For this review of Adventure
games for the ZX-81, 1 decided to
look at every Adventure and Adven-
ture-type game 1 could find. Thoy
vary a great deal, from the tradi-
tional descriptive type to real-time!
graphics games, so I have tried to
judge each on its merits rather than
compare one to another.
My employer told us recently to
take Adventure off the computer at
work, as we were running out of disc
space. That being such an unreason-
able instruction, I checked how
much memory it used and found that
the program and the data it required
occupied more than a quarter of a
million bytes, So. not surprisingly,
all the ZX-J31 games require 16K
RAMpacks.
The logical program to start with
is the Abersoft Adventure, which
attempts openly to pack as much of
the Crowther and Woods' original
into IfiK hk possible. As I was usually
hopelessly lost in the maze in the
Adventure at work, I was hoping that
perhaps lack of memory had forced
them to omit the maze from the
Sinclair version. Not a chance; on the
first attempt I wenl straight into it
like a homing pigeon. The maze
seems like quicksand; the more you
struggle to escape the deeper you
sink.
At that point I asked a friend who
had acquired a good knowledge of
the original Adventure to try from
the beginning. She found that all the
locations and objects were in Iht;
correct places, although the location
descriptions were shorter. She even
discovered a new area she had not
entered previously.
The program is written in 13K of
machine code and l|K of Basic, with
more than 70 words which can be
recognised as commands or objects,
and a large number of locations. The
name has been written with remark-
able efficiency; location descriptions
are built-up from individual words
and phrases rather than stored en
o/oc. Being machine code, the pro-
gram is very fast. At any time you
can find your score and also save
your current position on tape to con-
tinue later.
At £10, it is an expensive program
but it is a remarkably good version of
the original Adventure and well
worth the money if you want to see
what sparked the entire process.
Hilderbay is best known for being
the "serious" software company,
supplying business programs, but it
has also forayed into the world of
games and its Gold is a non-graphics
13K Adventure written in Basic, The
object is to search for gold hidden in
a network of caves and mines in the
Yukon. All instructions are entered
as a single letter, O for Open, G for
Get. including references to objects
such as Gold and Keys.
There is a sizeable network of
logical I y -connected caves and
rooms, although there are few
objects, ff you manage to find the
gold, things change mysteriously
and I have not been able to extract
the goodies yet. At any time you can
learn your score and there is an
18
SINCLAIR USER May ittiu
adventur
games
the dragons!
added bonus if you manage to escape
with the treasure.
Hilderbay is offering a 48K
Memotech RAM peck to the person
who achieves the highest score
before the end of July but 1 do not
th ink m y 46 wi 1 1 be in t he runn in g ,
At £fl h with a word game included.
Gold is reasonable value but could
SINCLAIR USER MayiaBZ
have been better with a few more
objects — and word rather than letter
input.
Bug Byte offers two Adventure-
type games, the latest of which,
Dictator, is a brilliant simulation of a
banana republic; since it has no loca-
tions, no objects, and no movement
of any kind, it is not an Adventure sot
have not included it.
The other is The Damsel and The
Beast which is a graphics-only yK
Basic game. The setting is an unlit
palace of 35 rooms, containing a
beast for bashing, a damsel for
rescuing, and a few holes into which
you can fall. That calamity should be
("continued un page 20}
Ifl
[conJiriiJfld from page 1 9 J
avoided by using the limited supply
of torches available and you are also
provided with some powerful clubs
if you should wish to knock down a
wall or kill a monster.
After being set-up randomly, the
layout of the rooms does not change,
so a logical approach is rewarded.
Movement, and the use of clubs and
torches, is by single-letter com-
mands and the beast continues to
move of its own accord while you
decide what to do,
The game is not desperately fast
and while in progress there is little
to look at, although you are provided
with a map of the events at the end.
There is no score given but there are
three levels of play and I found even
the easiest of them difficult enough.
11 is not a game for Space In voder
addicts but if logic and patience are
your virtues, it is one to consider, It
is on the expensive side at £6.50.
Quest from Serious Software is
dearly ba<;ed on the non -computer
Dungeons and Dragons fantasy role-
playing game, with the computer-
man pitting his strength, constitu-
tion and dexterity against wander-
ing monsters. It is a non-graphics
game written in 12jK of Basic and is
made up essentially of vampires,
rats, werewolves and suchlike. If
you can keep the fiends off your
back for long enough there are
potions, keys and other objects to
be found and substantial amounts of
treasure to be acquired,
Movement and fighting is done by
single-key input, which can be con-
fusing, since the same key may mean
different things depending on what
is happening around you h e.g., F may
mean move Forward or Fire magic
arrow. You can always ask for a
status report and, if you can put
together sufficient treasure, the
delights of different levels are
offered.
My reactions cannot cope with
this one but at £5,95 for Quest plus a
Star Trek, Mastermind and Reversi
included, it is good value for the
nimble-fingered.
Adventure from Simpson Soft-
ware has its origins in the Crowther
and Woods' original but is set in a
mythical castle containing evidence
of an eslraordinary mixture of living
beings — hobbils, dwarfs and pirates,
among others, It is a non -graphics
adventure with 25 logically-connect-
ed locations written in lljK of Basic.
The method of processing instruc-
tions entered by the player is
unusual; instead of checking for
individual words as most Adven-
tures do, the input string is compared
in a large series of if-then state-
ments That makes it reasonably fast,
hot means there is a very limited
vocabulary; e.g., you most refer to a
Ming vase t not just a Vase. One
weak point — answers to Yes or No
questions are not validated, so a
NE WLIWE stops t he program,
There are plenty of treasures
dotted about, a hidden lower level,
and a maze into which you can fall. A
score is kept, though my earliest
attempts ended in negative scores. It
is an onpretentious program, reflect-
ed in its price of £3. [t would make a
good introduction to anyone new to
the concept of Adventure who wants
to start with something reasonably
simple.
Phipps Associates offers three
complete Adventures on one tape,
plus a detailed instruction program.
All the games are written in 1SK of
basic and the first two are based on
Trevor Toms' Ad venture- writing
program from his book The ZX-%\
J'ockei Book, Several months ago I
typed -in the program and was
impressed but I felt that it would be
loo difficult to use and that the range
of locations and objects would be too
limited. The Phipps tape proved me
wrong.
Greedy Gulch is set in a Wild West
ghost town with more than 20 loca-
tions, plenty uf objects which have to
be collected and used in a logical
sequence, and a vocabulary of more
than 50 words. It is not particularly
fast — around 10 to 12 seconds to pro-
cess instructions — but it has some
graphics in the form of a simple but
useful map. There is no score hut to
compensate there is a hint feature.
The secood is the non-graphics
Pharaoh's Tomb which has more
than 60 locations, made possible by
giving only short descriptions, and
more than 20 objects. It runs slightly
faster than Greedy Gulch, despite an
even larger vocabulary, and has a
score but no hint feature.
It shares with the first program
some poor spelling, although Phipps
Associates is by no means the only
culprit where that is concerned.
Magic Mountain has witches,
wizards and spells, and an assort-
ment of mystified objects. It also has
a maze which, as usoal. [ discovered
very quickly. It took me a solid guilt-
ridden hour of cheating to gel out,
despite using one of the hints avail-
able in the form of cryptic cross-
word-type clues. All three programs
are excellent Adventures and at
£5.S5 complete they are undoubtedly
the best value for money of all the
Ad ven tures 1 have seen so far-
Next month I will examine 12
more programs, including the three
machine code Adventures from
Artie,
Aberson, 7 Maesafallen. Bow Street Dyfsd
SY24 5BA.
Hildarbay Ltd. 8-10 Parkway, Regerus Park.
London NWt 7 A.
Bug Byte. 90-100 The Albany. Old Hail
Sireel, Liverpool L3 9EP.
Serious Software. 7 Woodside Road. Bir*lny
Kent BR 1 2ES
Simpson Software, 21 Tutties Lar>e West.
Wymondham. Norfolk.
Phipps Associates, 99 East Street, Epsom,
Surrey KT 17 1 EA.
20
SINCLAIR USER May 1982
ZX81
Basic
Learning
BASIC
with your
Sinclair ZX80
Robin Norman
This hook n-fJi be ol great rates to all
ZXflfl owners H re^s y<5*> OflwJo get
ihg ZXSft workmQ. now to program it
and ho* to sref Jh*b*#tO"f riM
Ctfnrairts *W rfte wif n-jmairon ngeossS-'y
ro u» Jfie SfJiciatf ZX0(J ft? the full
plus I J spwr-iafy wiiftenjj'ojfams
un#varJaMe etae-w-'JS'F
o 40B or jot 7* f60 pages
Microprocessors
for Hobbyists
Ray Coles
Aoapled i/om a popular »jhs of
articles in Practical E*Kfmnm r"hr.»
ix>o* )a*« We reader srep f ifep
fhrougn the myslB'iw-s of 'h*
rrucrcvOr^ssoi' expand its iflsJrue-froo
SOt, 'f» Support components SUCrt*B
memwmsurMicammu/vcattan interfaces.
and the use at trie mtcropnKOSto* in
home GCv73p^r0f s
406 004 74 2 92 pages
£3.95
Robin Norman
it you have a ZX8>. or are thinking of
buying one, this book wli fell you ait
you need to know to get the
best from it
ThaZXBi Baste book covers ins
Basic tK version, the additional
facilities ottered by the t6K
expansion RAM and how to use the
Sinclair IX printer. There are 14
original programs tor you to run on
Ine machine (tor 1K and l&X versions).
ind tor those contused by computer
jargon (and who isn't?i there is
a glossary of technical terms.
Robin Norman assumes no inttiai
knowledge of computing and bis
undemanding writing style is a
perfect beginner's introduction
0408 01778 5
17$ pages
£4.50
OS, A on
Personal
Computing
Peter Lafterty
This Hock wW help Mjone *no
wWin 10 isa m about personal'
computers stnri ffio uses to which
they can tie out. i r desenfres the
dewlopmen I nfthft jW/S'Oria '
computer, BKptama its operation antf
outlines ihe piinciptaa of
programming:. A chapter on
applications sury&vs the many uses
oi these rerrarHaokt mac^i"**
408 00555 6 96 pages
Coming shortly...
26 BASIC Programs
for your Micro
Derrick Dain&s
Hmnt is * colttctKin or 56 new and yarmrtgarrmi
progfams. trom spotting: rests re JtngmannB"
fr\ j.rriri a Thty ire greeted From the most
erBtnentary, usable on 'he s"wp***. r fcflvm*
campy^ to \t}nff«t anti mote compter; programs
suiffloJe tor more advanced rrtacttin**-
Oerrick Dairies Has mmttafi the games w ah easy
suoselot BASIC so thai rh» naadet mil have no
dittitutlv in iransltltfiQ tfiem for antf microcomputer
€ach program isdeHnfjeo'irta to voir anrf mloitrra nve
style, with a list &t vtf Utiles and memory size required
plus a program irsiino. and sample r^fl
Ttiebook istdeatto' nfifab^rif 4 smce <t Helps improve
techniques tor writing successful prvQra>ni whilst
aisc providing polity t)f entertainment
£1.95
ORDER NOW- from your local bookseller
£4.95
ISU. tfb/8i\
tn case Qt difficulty send cash
wttrt order to Patricia Oavi*s,
Marketing Manager at the
address shewn
l\lfewnes Technical Books
il YJ Borough Gieen.SevervoakaKent TNI5 8ffi
ZX81 HEWSON CONSULTANTS ZX81
HINTS & TIPS fortheZXSI
bv ANDREW HEWSON £4-25
■TGood i »Ltic a rid t| une tavri n a\ i ng j v lt> i nf ipcnM *e i*a j i>rai.*|um nij m^nl h*
orpro^dmrom ii f*|*fiince , "-YO ; U(U 1 OMPI.TER No*8l
'"Fteclleml . ver>BM>J value Tor mmic>"'?»VNC.
t"hapKTM'H iia^ngSpacr (, ndersHinilinfiLhTlJi^r*!*^ File. ..ton veflini
ZX80 Frosttnii . . Ciuimin^ PnifritiTiat pais data bf Wvtti, nfograms.caU
HfcnotJMiBft«ca«ette,<*tailJHhdHlfiIe*] Mach met "ode Pmgramn* me.
likid.tilil. ^ave inJ df^HiiKiKhtrt lchJti
H ..Mines j!id pfn^nim!.are ifaiierMl hberilli Ittrimghnui i he lent and [be final
chapter i,H-iiuis(ioFl»tl ".i uwt'ul, rnii.-n.'sljnjiandenUT'minin^ pru^rams.
16K RAM £34.95
\ ii'ni|iialit> add-on IftK dj nam if memnri
^rHfialhdriigiKdforUicZXa I Simply plant
mlulhe ponatthe hat kpt'j«ur SmL lair tan
(KunerfHivrttijuiittion »-itNthr f\ prmler.
Veal I j puci.»ip;<3 1 n a tilack plan! k ^he-l 1 1 n
nuiirh sour ^\fcl . IntrcJihlc ^ jliif. wfiypi]
-^t■.^t■■ 1
MEMOPACK 64K RAM £7900
Developed hj MemtHevhllinajnafmgMK R \MmTd-,rt<i*ura [wwtrhupri^
Simpl> plut*JKStl) andflnnh iMcthefairportOfycnifZXS! < jnheuwtlwuli
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* I " p to 1 5 K of ruMt nfiigra-tn af ca
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Z80 OP COOES £1.45
AmasLlorthehrKiniicr an<11 he <r\pcnriiLca programmer alike Irinnandy read>
nekoncf hsisali wtfi plui/SO moKhiiK««deimtfifs^t(inf in dift-invil »«J
hnadi^imal with their mitsminriics. Etch < )r' ,1<Jl " i»«»swncll) ciiplamFil HHl
n r'cpent'rd. Supplied m a protcctue Immpartiti malli'l 1iir l ;;i'.> nfertitrt and
durahili!;
16K SOFTWARE SPACE INTRUDERS
+0 aden ships in c-ach^dumlrnsn MlactWd
display. AulnmalK option -lhemai-"hihF
ludotteltjerVWrillen ifl
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£495
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PROGRAMMERS
TOOLKIT £6.50
^ iL \ou svntiTia >^ur nwn programilorthe
ZX8H Tien iiwuitr ["OOl klftadolhe
dnnacy *tw* . Copy n into HAM oefore >ou
drift tottftt I htn ; ou urill hjwe it at JWUf
finjerlipv. t'omp'* hf nil te LtNl
REM'MBLRinuludingGOTtlsiinil
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liwnpkctrfBwte COdfe ami rU I'l M I- all
DceurmricttoTii: nw*er»teefam Basic imrs
wrrttEOn
LANGUAGE DICTIONARY £3.75
^fl^»•^oucan^■il^J^u.tl ^^lU^^'■vk^ I nghsh French. fnjtlish Vniihiiin.liiiiunary
wkFO«rLANaJAOEWCTrONAft\ t'lTjATElheenmr, M \k< Hfora
u<in] i .t REATEane»ditlmnar> andS'Wi ntMiiopeallM.ith Ihestme lull--
dcla i led program
tK STATISTICS £3.75
Three prt^cnin'isnfnhei'ini! i amn"ttf
1 1 i St at id ici - pHrtB the c ur rent mean an J standard dtv iat ion after cath i alue n
entered.
1 1 Kf grtssi nn - prints I he t ur rent mean and standard des iilinn nf (he ) »rid s
v aJuts andu he i nlereepl * »d slope of the mrt»i«n line.
in Trend-priniFithetuTrentmtan ard standard dei lamsn id'thes ands values
and the ilHC rL-epi and sJope oh he f und 1 1 nes.
:K HISfJl \Mt P TI-ST-pnntslhcv-urMMvaJueoHlifChisqiijKJsiJli'Jitand
inireurfcnt sjimpli- m/c
,ti ( ,k \PU PLC* I -pints a tf rarh ordataentertd ffomthe keyhevard
Cheque with order or quote Access or Barclaycard nu mber to:
HEWSON CONSULTANTS, DEPT SU, 7 GRAHAME CLOSE, BLEWBURY, DIDCOT. OXON OX1 1 9QE.
all phices imcluSive Of vAt and p&p ^ e ' ; (02351 850075^, ^
SINCLAIR USER MayM2
21
Exploration into t
Stephen Adams demonstrates how free space on the Memory
map has been utilised to make the ZX-81 more flexible.
WHEN Clive Sinclair
designed his basic com-
puter, it was to contain only
three things within the memory
map, the area where all the instruc-
tions to operate the computer are
stored. The area is easily accessible
by the Z-80A microprocessor and it
is easy to program uses for it.
The memory area is divided
into 65535 locations (64K), by the IB
binary address lines (A0-A15] which
are used to indicate the loca-
tion at which the processor wants to
look.
Sinclair required only a place to
store a program (RAM), a place to
hold instructions to operate the
computer when it was first switched
on [ROM) and a location in memory
which would translate the TV pic-
ture. So he divided the Memory map
into three sections, Q-16K for the
ROM. 16K— 32K for the program
RAM and 32K— 64K For the TV pic-
ture. That was done by using only
the top two address lines Ai4 and
Al5, to tell which section was
operating at the time.
This divided the Memory map
into the four sections as shown in
figure one with the ROM and RAM
repeating itself again and again.
The address line A14 is used to turn
on the ROM when the condition is
Binary and when it is Binary I
the RAM is turned on. The
A15 Address line is used to
operate the hardware which puts out
the TV picture; it operates only when
At 5 is Binary I.
As AH can also change slate from
Oto 1, while A15 is operating the TV
hardware, the RAM can be used
to store the screen display. The soft-
ware in the ROM makes use of that
fact and has only to pick up the
address where the screen is —
between l E>K and 32 K — and then add
32K to it to put it on the TV screen,
The Only problem with this system
is that ROM between 32K and 4flK
cannot be used as it would
upset the TV picture. It also
meant that the ROM appeared in the
8K to 16K section, blocking out any
other use for it, as it could
not be turned off.
That was the situation which
existed in the ZX-0U and only inter-
nal modifications to the computer
circuitry could sort it out. The
only place left to put new devices
produced by other manufacturers
was to steal some of the RAM space
to fit in the new device. That
was done by turning-off the RAM,
operating a pin on the expansion
port called RAM CS. That was
included in the design, as some
method was needed to turn off the
IK of internal RAM when the 16K
RAM pack was fitted on the back.
That was because the IK RAM
was repeated through the whole of
the IfiK section and would get in the
way when 16 separate iKfl were
installed instead. When the 16K Sin-
clair RAM was installed that was not
possible as it not only blocked-
off any connection to Ihe expansion
port by covering it, but also used the
only free memory locations It
also did all of its address decoding
inside the pack, so coul d not be
turned off by operation the RAM CS
line,
When Sinclair saw that there was
a market for his computer and that
other manufacturers wanted to
OS6 it as a basis for experi-
menting with computers, he re-
designed it, giving greater flex-
ability to the memory map, The
result was ihe ZX-flt .
The internal design was much the
same as the ZX-80 — figure one — but
this time an extra connection in
the expansion port had bee n put to
good use. It was called the ROMCS
pin and by ope rating it in the same
way as the RAM CS pin, the
RAM could be taken out of
the Memory map. This was located
on pi n 23 B on the expansi on port and
caused some chaos at first, as it was
found that the first Sinclair allempf
at more external memory, the 3K
RAM pack, did not work the ZX-&],
This was because inside Ihe pack the
pin was kept at apermenent Binary
and prevented the ROM from
being turned on. The only solution to
the problem was to cut the connec-
tion lo the pin within the pack,
leaving it unconnected to anything
within thepack.
People could then from the out-
side of the computer, free some
space in the memory map for their
use, Thai was a great advantage,
nx many of the people who
had bought the ZX-fifj ZX-81
did not want to have to fiddle inside
their precious computers with a
soldering iron for fear of damaging
them.
12
SINCLAIR USER Mu>'l!NU
memory
map
the memory map
II left many firms, which had cut
their teeth in the ZX-BO with a vast
market For adding additional boards
to the ZX-81, which could greatly
expand its flexibility and use, Many
of Lhe people who started in the
field have now left their original jobs
to work full-time producing add-on
boards fur the ZX machines,
[I also led every manufacture to
r
try to use the same areas for differ-
ent uses. Also because the ZX cust-
omer whs not willing to pay
a great deal for any extras
to his machine, costs had to
be cut to fit the market. So
they took a lip from Sinclair
and reduced the amount of lines
they osed for addressing.
Thai meant that we had the same
problem as previously, that one port
covered more than one memory
location; some cover up as much as
8K. That of course* means that when
one device is using that area, no
other devices can be used at
the same address.
Figures two, three and four, show
as many of the devices which 1 could
(continued un pujfe M\
Sinclair's Intended Memory Map,
14*
ZX-BO
ZK-B1
USED
FOR
TYDI5PLAT
1*K
RAM
PACK
IK
INTIRNAL
HAM
14 K
RAM
PACK.
IK
INTERNAL
RAM
41 K
4KROM
IK
ROM
HOT
USED
UK
USED
FDR
PROGRAMS,
STACKS,
SYSTEM
VARIABLES
4KROM
CAN RE
USEDhF
•K
ROM
4KRON
ROMCS = +iV
4KHQM
UK
CAN RE
U5ED
11K
MM
PACK
CAN RE
USED
RAM
PACK
1 FRANCS
PtN = *|V
IFRAHCS
PIN = *S¥
I4K
NOT
USED
4KHOM
IK HAH
4KKOM
LLROH | K
DRESSES 4
ALL
ADDRESSES
ARE IN
THIS SECTION 4KROM
OK
IK
ROM
IK
ROM
IK RAM
CAM BE
USED IF
ROM CS P1N = *JV
HfcROM
Ftaml
Memory Map 0-1 6K
14K
14414
12J52
12208
11244
' '.HOB
10240
Floppy diic
I O part*
Floppy
di«
print+r/
graphic ■
ROM
4704:
8449
R192
Floppy
*,O.M.
T4SO
Hncn
Hirdwire
chrt board
MAfdwmr* M j„ _ C »„
c hrf b pird
KDI100 i„ w .ritki
Himo-
t«h
S4K
RAM
pack
<Ba.nk1)
OS
hi-rei
ICfMIl
ROM
MemD-
44K
RAM
pack
(Bank 2 >
Ttchno-
m*tic
port (xxl 1
Uier-
dcfrncd
f rap Kici
HAM
dkVonit*
m
grajthiei
ROM
port!
3k Suit ROM
Figure?.
SINCLAIR USIiR Mo y 1982
23
{continued frompaipi 23)
find, plus their addresses. They
also show, by putting into different
columns, the devices which cannot
be used together. If I have omitted
any devices which fit either the ZX-
00 or the ZX-81, would people please
send me the name and address of the
manufacturer and what it does and
how many addresses it c;overs. That
includes all the ports if it contains
more than one,
1 can be contacted through the
national ZX-80 and ZX-ei Users
Club at 44, Earls Court Road.
London W8 6EJ. It is only a
post box, so please do not
call expecting to see someone
connected with the club.
[ have included two RAM
expansions as they all have to start at
1BK and work their way upwards.
That memory must be continuous
for basic, as the program would
crash if it tried to store memory in a
RAM location which whs no!
there.
This is the first attempt of
which I am aware to try to
catalogue all the devices the
ZX-aOand ZX-81 can use, but do nut
write to me for names of the manu-
lactures of these items, The only one
lacking the manufacturers name is
the floppy disk system which is
manufactured by Macronics. For
more details on these devices, con-
tact the manufacturer.
Memory Map 16K-32K
])«
Q* H».n
tound' port
I Hardwire
port
1
16K
lua
3 1951
I
BD3100
lyitBmfor ZX SO'*
RAM
31*44
»K
11K
16 K
packi
Tec hn omit ic IX 80 port
24 K
UK
DCrpert
MS04
ZOK
18 K
17*
1£IC
Minimum RAM far ZX BO »rvd ZX Bit
on *witc h-o-fi
Figure 3,
Memory Map 32K-64K
14K
Minimum addrcii aviillb Ic
Sinclair
Htm«tnh
tv diipiir
4WCaadjMW
1 16k HAW;, (dofinetd»itrupt
441312
■
4*K
TVtfttatey)
G.Conl'ol
QS
■oltan
Audio
M
hi-rat
*
Camputan m
•Grata
32K i
44 K
'im
a
*nd c
h
111K
HAM i
4JK
4
picm K
(IMKtt
aad
inllX
bznki) 4
40 K
■
radditth
r
A
UK
port i
N
P
*
t
14 K
MK
i
*
QSr.hr* board
JJK
UK
Figutfic*.
Z4
SINCLAIR USKR Muyltffli
FULLER FD SYSTEM FOR ZX80/81
THE MOST VERSATILE SYSTEM FOR EXPANDING YOUR ZX
STANDARD KEYBOARD AND CASE
Fuller
\
[
111 MINI!
II M
1 1
■■■■■'■'■■■'■V.
w,l
EXTENDED KEYBOARD AND CASE
Fuller
Ml III I I Mil *
I I I I I I I
I I I I I I I I TTT1
I I I I I It I ITT
Keyboard Only Available!
Built £24,95
Kit £18.95( iP.P.BOp)
This splendid keyboard and case houses your ZX81 printed
circuit board, which is simply screwed into place, the
keyboard plugs into the ZX. You can now enter data with
ease. The 40 key switch board is a custom unit not made up
out of other manufacturers parts. The keytops are our own
design and have the ZX Qwerty and functions foil printed
onto them. Access to the user port, TV, MIC, and ear sockets
are as per the ZX case.
Built keyboard and case £36.70 or £30,70 as a kit plus E2. 10 postage
and packing.
The case is designed to house not only the keyboard and ZX
but also our motherboard, power supply. RAM cards and
two other boards, not necessarily of our manufacture. The
injection moulded case measures 200 mm x 350 mm x
60 mm and houses a 42 keyswitch board, the extra keys
can be assigned to other functions. The case is supplied
with a "Power On" LED.
Built keyboard and case £39.95 or kit £33.95 plus £2.50 postage
and packing. Motherboards £15.95 plus 8Qp postage and packing.
16k RAM board £35.95. 64k RAM board £79.95.
Sand SAE for details to:-
FULLER MICRO SYSTEMS, The ZX Centre,
Sweeting Street. Liverpool 2.
Announcing...
THE
BUFFER
MICRO SHOP
(NEXT TO STREATHAM STATION}
• • •
NEW SOFTWARE SHOP EXCLUSIVELY FOR
ZX81
PROGRAMS, GAMES. ' ADDONS"
* * •
MOST OF THE MAIL ORDER ITEMS ADVERTISED IN
THIS MAGAZINE AVAILABLE OVER THE COUNTER
* * *
LOADING PROBLEMS? TRY OUR INTERFACE
BUSINESS & TECHNICAL DATA HANDLING PROGS-
PROPER KEYBOARDS; CONSOLES; VDUS
• * *
374A STREATHAM HIGH ROAD,
LONDON SW16
Tel: 01- 769 2887
SAE A PPREOA TED FOR CATALOGUE
Z-AID |
VERIFY Do you SAVE sin times and wonder if every
copy is corrupt 7 VERfFY will make a bit-
for-bit comparison of your BASIC program
on tape with the contents of RAM and tell
you whether you have a good copy Essen-
tial tor serious program development,
VERIFY even checks taped variables,
IV1 LOAD/MS AVE Load and dump any area of ROM or RAM
to and from tape You can specify
addresses in decimal or hex, or mix the
two.
APPEND Add a BASIC program from tape on to the
end of onE in memory.
VPTR Find data or variables within a BASIC
program instantly: dozens of applications.
Z-AID is an ongoing series of packages which provide a
comprehensive set of utilities for ZXS1 I16K) programmers,
similar to those available for more expensive computers.
Purchasers of this first release can obtain special discounts on
future additions to the range. Utilities now under development
include DATA/READ/RESTORE, TH ACE/SINGLE-STEP.
GRAPHICS and INSTANT SORT/SEARCH. AH Z-AID utilities
axE fully documented with detailed, lucid examples of use and
require no knowledge of machine language or the ZX81
operating system.
For a FREE leaflet giving details of our introductory offer for
Z-AID, just send your name and address to:
Em jay, 17 Langbank Avenue, Rise Park, Nottingham
NG5 5BU, England
SINCLAJR USER May MR2
2S
KEYBOARD £25-70
Wo soldering - just plug in
Proper switches
Two colour legends
RAM/PRINTER operation not affected
K I T G2O-50
CASE 10-30
EXTRA KEYS
48 P
Nllllll ■ I.J I 111 ■ I in
IN OUT PORT
24 Lines (in or out)
Controlled by (basic)
Built £16,95
Kit £18.95
CONNECTORS
23 Way female £2.95
23 Way male 1.30
30 way ribbon 1.40
Getting acquainted 4.95
Mastering machine 5.95
code
Programming for realb.
applications
REDDITCH
Tape for above
ELECTRONICS
11.44
DEPT SU
21 FERNEY HILL AVENUE
REDDITCH
WORCS B97 4RU
ENGLAND
TEL 0527 61240
Send SAE for free illustrated
catalogue (5" x 7")
prices include VAT and postage.
under £1G add 40p.
add £1.80
Orders
Overseas
UMCUTCJUW
WSA
2B
SINCLAIR USER Muyiau
16Kram
THR SINCLAIR IfiK RAM puck
arrived in January, ltfttl for the
ZX-8u\ At the time the design
was well in advance of any other.
Some 1BK RAM boards cost more
than £150 and the minimum size of
the hoard was 8im square.
Sinclair reduced the number of
chips required and reduced the size
dramatically to only Sin. by 3in. by
2in, There were numerous initial
problems with the design and there
arc still difficulties which cannot be
solved because they are built into the
system.
One of the problems was the
number of failures due to whiteouts,
as they have been described. Thai is
mainly because of faulty RAM chips
which are not checked during manu-
facture. Tighter checks initialed by
Sinclair produced improvements but
unly after public pressure and the
major weakness of the RAM pack is
its edge connector. It can also be
caused by mains fluctuations.
The edge connector fits on to the
ZX-80 or ZX-ai printed circuit board
direct and that is smaller than the
RAM packs edge connector expects.
It also consists of shiny, sulder-
covered copper tracks and they
become very dirty. The only cure is
to clean them with methylated spirit
and to prevent the contacts becom-
ing dirty, by coating the printed cir-
cuit board with petroleum jelly.
Because the edge of the board is
smaller than the edge connector, the
RAM packs tend to wobble and thai
is not helped by the fact that the key-
board tends to lift the RAM pack off
its surface.
Originally< Sinclair had intended
that the 16K RAM was the only
extension which would be produced
for Sinclair machines and so cut off
anything connecting to the computer
when the RAM pack was connected,
So you need to use a motherboard if
you want to use the RAM pack with
other equipment.
The only other problem was the
way that Sinclair had reduced the
number of components for the RAM
pack, That was done by simplifying
the ADDRESS which turned on the
16K RAM pack.
The ZX-ao. for which the RAM
SINCLAIR USER MajrlWB
Sinclair's star add-on
taken to pieces
Adding the 16K RAM to your basic kit
certainly makes the ZX-81 even more
interesting. Here Stephen Adams dissects
the kit and finds it now over-priced.
pack was designed, originally used
only two lines to decode what
devices to turn on within the
memory map. Three devices are
used in the ZX-80 memory map — the
RAM, both IK and 16K. the ROM
and the screen display.
The maximum number of devices
which can be turned on from two
binary ADDRESS lines is four,
Sinclair uses the line A14 to turn on
both the RAM and the ROM. The
RAM is turned on to it by using
binary 1 and the ROM when it is
binary 0. The screen display is
turned on when Al5 is binary 0.
When the count is 4 or in binary 11,
both the RAM and the screen d isplay
are on and that is the only time the
display is sent to the TV. The RAM
therefore exists at two places on the
memory map. 1BK-32K (Al5 = 0) and
48K-64K (A15=l). As the 1BK RAM
[continued un fxige 2B)
27
[continued frrtm page 2?)
pack had to take over from the IK
internal RAM, it had to use the same
addressing system. The address
decoding is shown in fig ore one,
The RD and WR signals go to
binary when the Z-flOA micropro-
cessor wants to talk to any device.
Which one goes to binary 0. depends
on whether it in a ReaD or a WRite
operation. The MREQn signal is
called Memory REQuesl and tells
the device it wants to look at the
MEMORY MAP. The Al4 ADDRESS
line going to binary 1 and the MR ! ;Q
going to binary together turn on
the 16K RAM pack.
The At 4 signal is combined with
the two RD and WR signals, so that
the output of the NAND gate is
binary only when A14 is binary 1
and either signal is binary 0, indicat-
ing that the microprocessor wants to
pass some information to the RAM.
The output of those gales should
be binary from the OR gate which
is used to change over two of the
address decoders — figure two — to
look at the address lines A7-A1 3. The
reason those address Unas are not
connected directly to the RAM chips
is that they have only seven address
EDGE CONNECTOR
ADDRESSES
ADDRESSES
A7-A13
OR
GATES
NAND
GATES
)))))))))
16K
Ibrt
Figure 1. Addressing (he 1 6K RAM.
TRANSFORMER
pins. The RAM must therefore be
addressed in two stages, ROM
address and COLOMN address. The
address lines A13-A7 act as the
ROW address and A6-A0 act as the
COLOMN address,
The changeover from ROW
address to COLOMN address is
controlled by the divider chip, That
chip also provides the REFRESH
address used by dynamic memories,
such as the 41 IB (lfi x J hit) chips
used in the RAM, That is because
although lh* REFRESH signal is
given out by the processor at the
correct time, the address given by
the Z-80A processor is incorrect,
because the refresh register (R)
within the processor is used by
Sinclair for another purpose —
putting out the character set,
The dynamic memories must be
refreshed within a certain lime or
the data will be lost. The refreshing
is done by the chip — by reading-out
the bit and then writing it back
again — but it needs to know what
data location within the RAM to
next,
The data lines from the chips are
not buffered, so they can be placed
only a short distance from the com-
puter without causing problems. The
data lines within the computer are
also protected by resistors, so any
extra loading on to the expansion
port to use other equipment must he
buffered,
The 4116 RAM chips used in the
design do not require only a +5V
supply; they also need +12 Vend -5V.
! fin +12V supply can be replaced
with the+yVand it just works but the
-5V supply has to generate in a
different way.
A transformer is used — figure
two — along with a transistor to form
an oscillator driven from the +9V
supply. The transformer then steps-
down the voltage created by the
aacUlaioi toSV. As both sides of the
transformer are isolated from each
other, the voltage can be rectified
into a DC voltage, with the positive
terminal connected to the 0V line.
Thai is then passed to the RAM chips
alone, as the current generated is
very small. The transformer also
[continued on page 2&1
28
SINCLAIR USER May 1 082
fcantinued from page 2R)
creates the characteristic humming
or buzz of the 1BK RAM pack.
Since Sinclair produced the RAM
pack, memory RAM chip prices have
fallen dramatically and the price of a
4 1 fi chip on the retail market Is some-
where in the region of 45 pence. The
design in early I9fll was inexpen-
sive, very efficient and small in size,
but it has not been improved to
date, neither has the price fallen in
response to the fall in the price of
chips,
The ItjK RAM pack therefore is
looking over-priced to people who
can now obtain a better version— no
humming and better reliability — for
about £35.
Manufacturers have now had
sufficient time to produce a design
which includes buffering — so that
more boards can be driven direct—
and still turns off the internal IK
RAM by holding the RAM CS
TO ADDRESS
CHANGEOVER
CHIPS
MREO
Figure 2. Layout of the 16K RAM pack-
line — on line 2A of the expansion
port — permanently off. They have
also produced RAM packs capable of
giving the Sinclair Basic 48K maxi-
mum RAM lo mm for program and
data, That applies only at the
moment to ZX-81, A 64K RAM pack
has just reached the market with 48K
of Basic memory and 6K of memory
for machine cade, swapping data
between programs. The cost of the
RAM pack is £79.
Sinclair has made plenty of money
from the In'K RAM puck and now
other people have produced cheaper
and apparently better versions,
including more memory than 16K,
for owners of ZX-Sls. I think it
should be retired and replaced with
a better or cheaper model, giving the
customer the advantage of the
reduction in chip prices.
ZX-81 &80
OWNERS
ACCESS TO THE
OUTSIDE WORLD!
Programmable INPUT/OUTPUT Pon based on
2Q0AP1 giving up to a total of 1 6 programmable I/O
lines all TTL compatible. Pori is NOT memory mapped
allowing full expansion of memory. Can be used WITH or
WITHOUT RAM PACK & FftiNTER.
Available in kit form or assembled and comes complete
with instructions, software notes and circuit ideas.
£13.50 in kit form - £15,99 assembled
INCLUDES VAT. .ADD 60c p&p
N nA/ ENCASED 4 CHANNEL
tVV RELAY BOX-toaddon
[o I/O Port. Changeover contacts rated at 240vAC/
1.5A- 1 10vACor24VDC/3A. Allowing programmable
control of mains for motors and lamps etc
£14.99 ■"»■
complete
ZX81 GAMES
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GAMESTAPE2.lciMGK gn'y f 4 95
■ K I A fi F I C HTE H You are fi^hl inj a t the «nrt «( (he universe
hew many enertiycBnyoude&tory? A graphic simulatmri.
PYR AMI D Can you move the PYRAMID? Matte ■ mistake am!
1 1 vri H col lapse I A thinkers gam e
AflTIST .become an ART lSr.il itn uk Ihe lOmeirai
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CATACOMBS
23*23.2X80/81 E4ge Connector £2 85 S.A E
Uijin.i,:! Cr^ar»Brl226grmi;|f J30 tai rleiails-l
ALL PRICES INCLUPf V A T ADfJSOp pip
THURNALL (ELECTRONICS) ENG.
DEFT S. 95 LIVERPOOL ROAD.
CAOISMEAD, MANCHESTER M30 5tfG
TEL; 061 775 4461
m
3D MONSTERS MAZE GAMESTAPE 4 ruf 1 6K ,„,I v 15 95
Upibcil icv able Graphics! Can you find vour way il
'-..■•XII ■. HnT.i^iinniivtHTO tail itifrn m 11 ■ T HEX
jrvd lESOltPrYOU 1 All in JO. yog wfl rvflver>»tnTfnYlh«nU la-
this before'
GAMESMARKED ' mcl Machine Code
J. K. GREYE SOFTWARE
Dept. SU. 16 PARK STREET, BATH.
AvonBA12TE
Trade enquiries wetcome
SINCLAIR USER May 1982
J<|
MICHAEL ORWIN'S ZX81 CASSETTES
CASSETTE ONE
for 1KZX81
CASSETTE TWO
Ten games in Basic for 16K ZX81
"1 had your Invaders fleact
cassette ... I was delighted
with this first cassette/'
P. Ruby than,
London IMW10
"I have been intending to write
to you for some days to say
how much I enjoy the games
on 'Cassetli One' which you
supplied mr with earlier this
month. Pie* a let . . into the
secret of your first time load
every time!"
EH. London SW4
Just two our of over 20
unsolicited testimonials.
INVADERS (1KJ
AWARI
■ ■ m m
R-HHR fl A A M H
■ ■ * n m • s « \ft n
Ann nnH ij ti
A A A M n
A A *w-
ii
■k .T
PHANTOM ALIENS
THft
,"i-l
f
El(L>fl»T
£
T^
y
- -
.
v_
^
^
fDMW
-in- r
11 [E
PONTOON
Tut *i»«i m.'. m*»»
rnjn f.cfDr is eihi
BUG SPLAT
rf»ri
15 ClfH
I WILl 5T 1 E I u[Th 17
Cassette One IK machine code programs:
React, Invaders, Phantom Aliens, Maie of Death, Planet Lander,
flouncing Letters, Bug Splat.
1K Basic Programs:
I Ching, Mastermind, Robots. Basic Hangman.
PLUS Large screen versions of Invaders and Maze of Death, ready
for when you get 1SK.
Cassette One costs C3.80.
vou htorUE Lrf>hl f 1
RECTANGLES
PENNY SHOOT
r\ 41 imy i*
i
UUUUUJ
Cassette Two contains Othello, Awan, Laser Bases. Word
Mastermind, Rectangles, dash, Roulette, Pontoon, Penny Shoot
and Gun Command.
Cassette Two costs C5.
Recorded on quality cassettes, sent by firs! class post, from:
Michael Orwin. 26 Brownlow Road, Willesden, London NW1Q9GL. iMail order only please!
If you own a ZX80/ 81
then you need the
ABACUS CONTROLLER
Developed to
eliminate tedious
swapping of plugs
when LOADING Of
SAVING programs
on cassette.
One switch
operation allows
selection of TALK,
SAVE, CUE and
LOAD modes. Using
a built-in
microphone / speaker
to allow fast and
reliable program
naming and cueing.
Send Cheque Or
P.O. for £12
including p&p to:
ABACUS ELECTRONICS
186 St Helens Avenue
Swansea, W. Glam.
Tel: (0792) 50282
2X81 owners
Protos
Keyboard is here
At last! A real full size keyboard in a top quality case for
your ZX 81
Simply unscrew your ZX-81 printed circuit board from its
black Sinclair case and plug into Pm -
FULLY BUILT £64.95 inc. VAT
• More accurate, faster typing with bigger and real keys
• 40 colour coded key- lops for easy readnm
• Hohust, 'big' computer construction
• PC B prepared for more add-ons to come
• New edge connector provided for Sinclair and other
manufacturers' penpherals
• Key legends can he changed for future new ROM functions
• Sinclair PCB fully enclosed and room for much n.
If you feel you've outgrown your ZX 81 don't sell it for
peanuts and move to another system. Add it to Protos
and make your ZX 81 grow
For details, lafge SAE. pJease. For orders add £2.50 post and
packing. Cheques to 'Frome Compuliny
Protos
Computer
Systems
Frome
Computing,
20 Ashtree
Road, Frome,
Somerset,
BAH 2SF
i/
m
SINCLAIR l.'SEK M«ylt)W2
ra
for both the ZX-80 and the ZX-81
F. U
" ^^A^
YOU ARE in command of a
squadron of tanks in Minefield,
In* iK ZX-81 game. Before you
lies an enemy minefield through
which you must pass. How many of
your tanks will be lust finding a safe
n.M.j
When you run the program, the
computer will generate a mine-
field — a different one each time you
plays Drive your first tank across the
screen, usins the forward, up and
down keys. Be careful not to use
other keys,
If you hit a mine the tank blows up
and you must try again wit h the next
tank. They are multiple mines and
will destroy every tank which hits
thfc-m. Your score is displayed at ihe
top of the screen. If you are success-
ful in finding a way across. Ihe pro-
grams stops.
You will find you become profici-
ent at avoiding the littered battle-
field as the game progresses. The
prngram was adapted by Tim
Hartnell From the original program
written by 1 S Howson.
©JSl low sun. 1982
SINCLAIR USER May 1982
iO
LET 5=PI-FI
15
LET X=S
10
LET C =
30
- - -.< r
. =— - _ - _ r
4.S
PRINT AT
se
LET H=1Q
- .— ,
rtT S'li-
PR TNT RT fi,, E.
a a
PRINT AT :•
PR INT AT
110
r-E *
130
I s .:>
170
RND
ate
" 50
270
5 3.. 5
■ H .■ 6
H ,B\ "
' THEN
LET C»Ci
IF INKEY$t>"
INKEY*) -23
IF C=X THEN LET B*B+X^X
IF C<X THEN LET R=fi + 1 5 -C *.2
IF 5 = Tyi T iWDi3a) Of? A = XNT
0) THEN GOTO 210
GOTO 60
PRINT hT il.E,
IF 5
THEN
GOTO 3
itfdESH
gsns
---.Si; -*
31
ENGULF is for the lK ZX-80, by
Graham Charlton of Rise Hark.
Romford, 11 sets you against a
vengeful computer. After you press
RUN. a large black square will
appear. That is the playing area. You
have five controls:
7— UP
6— DOWN
5— LEFT
8— RIGHT
9— SCORE.
After pressing 5,6, 7 or 8, followed
be NEWLINE, you will appear as an
addition sign (+) with an inverse
space, CHRS(12B], next to it, Every-
time you move, the computer will
place a black square next to your
piece. The idea is to avoid being
trapped, or engulfed, for as long as
possible. Once you have been
caught, press 9 to see your final
score.
Charlton's best score is 154, You
can make the gamy slightly easier by
deleting line 280, which prevents the
computer piecing a black square
where a black square already exists.
The game shows PEEK! or and
POKEing to the display file in action,
The crucial line is 1QG. which finds
t h e beg i n n i ng of ih e d isp J a y f il e.
10 LET A = (J
20 LET E= 236
30 FOR C=l TO 21
40 FOR C=1 TO 21
50 PRINT"*";
60 NEXT G
70 PRINT
80 NEXT C
90LETG=0
100LETA=l+PEEK(i6396)+PEEK
[16397)*256
110FORC=0TO20
120 POKE A + C, 128
130 POKE A + C + 22*20, 128
140 NEXT C
150FORC = lTO21
180POKEA + 22*C, 128
1 70 POKE A+22*C + 20, 128
180 NEXT C
190 INPUT D
195 IF D>9 OR D< 5 THEN GO TO
190
20OGOSUB320
210 IF D=9THEN GOTO 380
220 IF PEEK [A + F)= 128 THEN
GOTO 190
230POKEA + E,0
240LETE = F
250 POKE A+E, 19
260LETD=RND(4] + 4
270GOSUB320
280 IF PEEK (A + F] = 1 28 THEN
GOTO 260
290 POKE A+F, 128
300LETG»G+1
3 10 GOTO 190
320LETF=E
330 IF D=5 THEN LET F= F- 1
340IFD=8THENLETF=F+1
350 IF D= THEN LET F= F+ 22
360 IF D= 7 THEN LET F = F- 22
370 RETURN
380 PRINT "YOU SCORED*"; G
32
SINCLAIR USER Moy\HB2
GALAXY PATROL, written by R
Stubbs of Shearing HilL
Nottinghamshire, plates you in
command of a galactic: patrol ship
which bears an uncanny resem-
blance tu the letter V.
Your V wing fighter starts with 50
gallons of fuel which decreases
slowly. The amount of fuel remain-
ing is in the top ri^ht of the screen; in
the screen printout the fuel figure is
33.
You re-fuel your fighter by hitting
any of the random fuel dumps-
inverse spaces. Each time you run
through a fuel dump, you receive 25
gallons. You control your craft by
touching the M key. Holding-down
the M moves you to the right; leaving
the keyboard untouched allows your
craft to drift sideways.
The game ends and your score is
displayed either when you run out of
fuel or hit an asteroid (asterisk).
Line 13D looks at the PRINT posi-
tions^ by the last PRINT AT in
line 110— and if it finds a 23
(asterisk] stops the game there,
printing the score (S) and using an
unassigned variable (D) to hall the
game If it finds a 128, the computer
knows you are running into a fuel
dump, so the fuel is incremented by
25— LET F = F + 25. Line 145 stops the
game if you are out of fuel, i.e.. if F
equals zero,
© r siubbs
GALAX
PATROL
programs
s
LET F=50
10
LET 5=P-P
SB
LET R=rS
"-■C
LET B = 13
*e>
LET C=X0
50
PR TNT RT C .
RND*30;
" *"
55
LET R-IHT (
RMD*10)
+ 1
57
IF R=S THEN
PRINT
PT 6,RND*
3©; "11"
?®
LET 5=5+1
75
LET F=F-Z
30
SCROLL
^0
IF B>2 THEN
LET B =
;B-1
100
IF IMKEVS-"
M" RND
Bi2S THEN
LET
s=e+s
110
PR INT RT ft j
e;"U u .;TfiB 23;f;r
1 i^O/
130 LET K=PEEK
(PEEK 1&395+256-
PEctv
153S3)
135
IF M=23 THEN PRINT
■ s; D
14-0
IF H=129 THEN LET
F=F+25
14-5
IF F=0 THEN
PRINT
5. D
150
GOTO 50
33
*
SINCLAIR USER Maytaaz
33
THERE ARE two versions oi
Monster Munch, written by Tim
Hartnell, in which you — the
inverse H — have to escape the
monster — the inverse M — on a 10 x
10 grid of Full stops.
Beware, however, because your
task is hopeless. No matter what yon
do, you will be unable to evade it for
ever and will be utterly and com-
pletely munched.
10
DIM ft i 100)
20
LET Z=0
30
LET M=FNO
40
LET H=RNC
= ■?•
LET X = INT CRND^a.* +1
60
LET Y-JNX fRHD*Sl
70
LET PsIN T ;RND^a+?»
80
LET © = INT ;RND*2-?-J5J
85
LET ft v X 1 _ -
90
LET a (P+10*O3 =H
100
REM PRINT OUT
11®
PRINT PiT 5.0:
120
FOR D = l TO 1G0
130
IF ft*Di=0 THEN PRINT ' . " ;
140
IF A*D>=M THEN PRINT jS" ';
IF fr(Di-H THEN PRINT ■ JS"' ;
150
1&0
IF 10*INT tD^10> =D THEN PRI
'*5T
17©
NEXT D
3L?S
IF Z=l ^HEN GOTO 190O
180
LET Rf+10fD) ^0
190
LET A(X+10*Y>=0
£00
PE >, -.'LRYER MOUE
210
Pf ■" 7ER YOUR MOUE N.S.
H.U.J
" . ■' (NE %t &.\, <?E . SU) J
215
INPUT B%
si?
LET 8$=£s$ + " "
220
IF B$(13 = 'N" THEN LET Q=Q-1
330
IF e*<l}="S" THEN LET Q=Q + 1
H4
IF B*(1;="E" OR EJCS)-'^" T
HEN LET P=P + 1
350
IF Bt(l)="U" OR e$l2J=* H U" T
HEN LET P=p-1
300
LET fi <P+10*Q> -H
400
REM COMPUTER RESPONDS
410
IF P>X RND X<10 THEN LET X-
< + l
420
-1
430
IF P<X AND X>1 THEN LET X=X
IF >Y RND Y<10 THEN LET Y=
V + 1
<i40
-1
500
IF 0<Y RND Y>1 THEN LET Y =Y
LET R lX + 10*YJ =M
600
REM HUNCH. . .
610
- I
Q00
IF X + 10*Y =P+10*Q THEN LET Z
GOTO 100
2000
PRINT RT 10fRNDsl0,10tRND*l
^.-.^HR. GOTCHR HUMRNl
2010
GOTO 200©
.&. .
4 ■ * * -
% & a a
.
- -. y -
*■-«■■!.
% ■ "» «
• *•*•■
* * :« «
* * w r r. m.
* *
t B iM.- ' ■ 1
X NT E R V G \ f R HO v £ H , ^
E,
MU , SF ,-z.U)
U4
SINCLAIR USER Muyl982
program
You enter your direction of
move— N, S. W or whatever, as
shown in line 210. The secood ver-
sion of the program is a little more
elaborate in its display and has; a
scoring mechanism. You can convert
the listing easily for game one Into
game two. You will need more than
1 K on your ZX-81 for the game.
10
DIM R * 1 x :
20
LET 2-0
55
LET S=0
30
LET H=Rt-JD
40
LET H=RND
-■■■■■:
LET X=IMT (RN&*2) +1
50
LET Y=^1NT -:D*5>
70
LET P ERNE
bo
LL
■r> 1=
LET R CX+10*Y) ^N
qg
LET R <P + 10*0.i *H
100
REH PRINT OUT
11CI
PRINT RT 5 f 0; "SCOPE ';S
IIS
PRINT
1SB
FOR D=l TO 100
130
IF RiD)=0 THEN PRINT ".";
140
IF fl(D)=M THEN PRINT '"fir.
IF RTD3 =H THEN PRINT "ffl" :
150
16®
IF 10* INT iD if" = D THEN PR^
NT
170
NEXT D
175
IF Z=l THEN GOTO 1000 * 1**'
130
LET fi«P+l@*Oi -0
193
LET R *X+1<2*Y> =0
£00
REM PLRYER HOUE
210
PRINT "ENTER YOUR HOUE N,S,
E..U., J
'■ . " (NE . NU , SE ,5U) "
215
INPUT E$
£15
IF S*(l>= , *5" RND Q>5 OR B* i
1) b"M" RND 0<1 OR B*tiJ«"C" AND
p>=> OR E*(1>="U" RND P<2 THEN GD
TO 216
217
LET BJ=C*+" "
220
IF B*(l) ="N" THEM LET Q=Q-1
250
IF BS(ll=' k S'- THEN LET 0=0 + 1
24-0
IF B*C1J="E" OR B*t21 ="E" T
HEN LET P=P + i
250
IF B* 11) =■■«■■ OP &*t2)="U'" 1
HEN LET P = P~1
260
LET 5=5+1
300
LET R (P+10*O) =H
4-00
REM COMPUTER RESPONDS
4-10
X + 1
-1
4-25
IF P>X RND X ; 10 THEN LET X =
IF P<X RND X>1 THEN LET X =X
PRINT RT 0,10; "H"; RT 0,10;"
*" ; AT . I©; ■■ M
430
IF Q>Y BnO Y<10 THEN LET Y-
Y+l
43S
PRINT RT 0, 10j ••B'-' .: RT 0,10; "
*"■ ; RT . 10: "" ""
4-40
-1
450
IF 0<Y RND Y.*0 THEN LET Y = Y
PRINT RT 0. 10; "B ' ; RT 0., 10.; "
*" ; RT , 10; " **
500
LET R (X+10*Y) =M
600
PEN MUNCH. . .
610
-1
900
IF X+10*Y=P+10*G THEN LET Z
GOTO 100
^COO
PRINT RT 10+RND*±O, 1®+RND*1
a ; "■
|Hfl., GOTCHP HUMRNJIB"
2010
GOTO 2000
SINCLAIR USER May 1962
35
DANIEL KING, of Headington,
Oxford, suggests thai the lK
ZX-81 Jackpol program could
be used for school fund-raising days,
charging fivepence for people to
press NEWLINE for a spin on the
ZX-81 fruit machine. They are paid
eightpence for iwu ideniiciil
symbols and 15 pence for three.
That. King assures us, means a profit
of 25p on 20 games, Simply RUN the
program, then press R to roll or
return.
If you have more than lK, enter a
routine to total your money-— wins
and costs — automatically, A HOLD
would also enhance the game-
Running the program gives a very
effective impression of reels of
symbols spinning, before settling on
one in each window.
^?r^aa<gj
PUSH
R FOR ROLi_. C03T , , .5P
TUQ PRV 6P. . .THREE PRY 1E _
2
5 . 13
DRTNT hT - , IP. 3TCM2l3Ajr . RT
: R^ '
'
p r 1 ?n" flTsTe f jsh r for r
^i_. C05T...5p-,PiT ii.0."TUQ Pft'v
5P . ,
.THREE PRY I5P"
5
IP INKEY$:;f"R" THEN GOTO 4
6
■7
DIM ft* (3)
FOR F = i T ~ ~
10
LET U*INt" CRND#?) +1
20
LET ft$ tFj =Bt(J]
■50
NEXT r
6©
POP P = I TO 3
§2
e OR T — 1 T G "7
sg
print rt e^ii+afF.jBttJ)
SA
NEXT <J
35
IF RND<.6 THEN GOTO 3 2
'—■ ^D
PRINT nT -5., lli5*F, H £ ' r j
f-;E;VT —
1C
IF' 'iNKEYC < >"R' J THEN GOTO ]
11©
RUN
©DKing.
[982
,
M
SINCLAIR USER May 1962
programs
ANDREW LOVERINC has
spent many hours with his 1 K
ZX-61 in Maidenhead in pro-
ducing the tine game of Catch, You
will see, when you press RUN, an
open box nuar the bottom of the
screen, Pressing a moves you to the
right, 5 moves you to the left. You
have to try to catch a rapid I v-
descending ball dropped from a
random position at the lop of the
screen.
To confuse you, and to introduce a
little luck into the game, a Jid appears
at random places above the box. If
the ball hits the bottom, or the I id, the
game ends and your score is printed.
- -
— —
L_E l i ' — i — t-
L ET ~ -~:IT i R N D *30 )
+ 1
-
~~ "T" C — -iT
:
LET = ^E
-
_ ■ • ■ C-i 5 B _■ ' "
TO
LET E=IHT CRND*30J
SG
PRINT ^T 19 . F ; " — _
**
PRI NT sVT 2 s '. n '; ■ ■ n
**
100
PRINT hT ai.fl; " U
11
l flj
-rp- T^l<EY$="5" i=j*3£>
= 2 THEN
l tr~ '
*=r i
-0
IF INKEY*="3 ' : PND
~. 59 THE
e*r
- . -
• ~- r*
IF T ' - -: .- ■- =E + 1
THEN GOT
L40
IF B=^t) P.MD CscR + 1
THEN GOT
15$
150
XF B-21 THEN GOTO
22>0
1
:~ 1 .=
" "^™" T^
_ _
1 20
L£"" D =D+ 1
Z:;t RT i . 2 , "SCORE l * , D
~! (J ©
FOR w = i TO 50
=35
ME XT
" L£
jTO 2i
25
rRTi;T RT Q.,G, "SCORE
330
hRL;3cl J-E4.
24.0
RUN
■■ Ami rpvv Levering, HJ62
10
INPUT MS
22
i i= JfiL "4-3"
355
FOR C-l TO 3
4-0
LET L=URL "0"
50
IF CODE M$ (LJ > 100 THEN LET
. =vBL ' 128
FOR N-0 TO 7
7-et
LET Z=PEEK i76s0+M+6s (CODE
13 EC J
-LJ J
33
FOR X = l TO ©
9©
LET Z=URL "Z/S"
130
Z-Q£?E M$[Ci ;>lt?^ THEN SOT
--it?
110
IF Z^:>IMT Z THEM PLOT B#C-
,Y-N
'1 *_• ,-L
SCTO 2 : _
_ 3 2
-=- ^z" - r t * -. —r~ —r **■ m —i ^ i. . — ■. - ■—- ~=~ -3 -* v— l » --
-4-0
LET Z-INT Z
ISO
NEXT X
160
NEXT N
1 7 2
NEXT C
' "l i' ".— *
130
IF LEN n$0 THEN GOTO ^4-0
£00
LET M*=M$ 19 TO J
210
IF Y<S THEN GOTO 00
2.--
■_- - •! :!!4
: _- L ~o
INCLfll
This program is a development of one
which appeared in the October 1381 issilt? nf
Interface. II is copyrighl Christopher Lowe, <S
[902.
THIRTEEN- YEAR-OLD Chris-
topher Lowe, who lives in
Edinburgh, says of his pro-
gram, Lcrge Letters, which fits a IK
ZX-81, thai it will allow you to obtain
an enlarged version of any charm
ter, ordinary, inverse— as In the
sample printout — or graphic.
Keywords or function commands
are not possible. The program jusl
squeezes into lK, using such tricks
as linn 40 to do so. To obtain a print-
out of your words, insert the follow-
ing lines:
215 COPY
235 COPY
And change line 1 90 to:
190 IF LEN MS < 9 THEN GOTO
235
SINCLAIR USER May i8&2
37
ADAPTED for a ZX-81 with
more than 1 K from a ZX-wi
program written by Stuart
Roberts, this Noughts and Crosses
gives you a chance to win now and
then, unlike many computer Noughts
ana 1 Crosses which are unbeatable.
Usually, the best for which you
can hope with such programs is a
draw from time to time. You move by
entering the number of the square
into which you wish to move.
According to the book Computers,
their impact and use, by Robert E
Lynch and John R Rice, there are
362,800 possible games of Noughts
and Crosses, if all games are con-
tinued until all spaces are filled.
This program will play some
40,320 of the possible gamfijL You
will find the program will run
almost without change on a ZX-80,
although you will n«ed to change the
PRINT arrangements slightly and
you will have to delete line 110 com-
pletely and replace it with a CL S,
NOUGHTS
and
CROSSES
o
Q
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REM BV 5
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NEJCT ft
LET E=B
let e =0
LETT N-*9
LE>T *=**
PRINT" RT
FOR rt-1
TF R.W
IF O (ftp
TF nini>
PRINT Bi
*JF>:t r
PRINT
PRlNl
IF N-l T
IF E-6 T
TF E=6 T
ir b-b t
r*T<5 cm
T LI OPT HkiPF^TS
TO 9
pR
ff,#J
ro 9
HEN C, J : U H ' '*»
fi> THEN. SOTO 400
id TNEN r-OTf +38»
HEN GOTO 46J
HI I- f BjHi
HEM GOTO 9 7]
Mf.N PP HI |
c?3fl
,4V
2 50
260
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. : *<?0
£20
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if o*s THEN i?nrci a .•
INPUT Z
IP 6121 i i7 THFN r,PTn P30
LET 0=Q+1
IF 7=11 THEN GOTO ZSP0
LBT M» ]
LET BlZi =e>
GOTO 100
1 r r Es ■ * > - 1 n
GOTO SO
fob R ■ C To D
IF BiR!=R THEN LET BlAi'lC
i r T r»r#e*
NEWT P
GOTO 93
IF BiSl-E "THEN CPTC 3&
let a ft i «ifl
GOTO 90
PHIHT 'O
LET P (R> =1
GOTO J.7&
PRI1*!T "X ",
LET PlUtl -4
GOTO 170
LET G =e
LET C=l
L r ' V 7
LET F-3
PC15IIB H
LET C=3
LBT D.7
LET F=l
COS '-IB H
LET E>*S
LET r=3
GO'S LIB H
lfr-T C-r
LET D=B
GOSII-B H
LET C-l
LET D«7
601UB H
LET Dm3
LET F=0
'7 OS '.IB H
LET C=J
LET f*«C
r.Di'je h
LFT L = /
LET D«9
GOS'JIS M
LET G-GM
IF Q«S THEN GOTfi Sk#
SOTO *9P
LET <>XO
Pf n
PRINT
R E F" LIS N
LCT E =C
Fnp *»»C TO D-
LET E=E4PlBl
LET R»R+F
NEST R
IF E»^3 THEN GOTO »ft#
If G*0 THEN BtTUHM
IF Er8 THEN GOTO
IF OH THEN RETUSM
IF E -£ THEN GOTO 3f9
IF G-B THEN RFTL'FN
IF t.B THEN 5PTO 3£ft
IF G=3 THEN RE-
IT r -y on B*4 thfm &tiTn ?7p
R ET I JO N
PRINT
POINT
f R I NT
PRINT "DO YOU UAHT RMilTMrE
T . . , ■ ■ ( y Oft W > ,J
INPUt H »
r.; ■
IF K«0"*«" THEN RUN
: .
PHJNT "OF, TKBWf-S FOB PLflVI
a 9
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in ft
Q X
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143
4 9
" ■ y
4 9
:<h
SINCXA1R UHliK May 1982
X81
users
I need more memory! please rush me the fully
assembled, tested and guaranteed
'BYG BYTE'
16K RAM PACK
Name
Address
Make all cheques & PO's payable to:-
Phoenix Marketing, Oakiands House Solartron Road,
Farnborough, Hants. Tel: (0252) 514990
FULLY INCLUSIVE PRICE
£34.95i
ZX81
ZX-MC
• ELIMINATE MACHINE CODE PROBLEMS wilh ZX-MC - a new machine
code onbug/momior for th-aZXBl T§K
• ENTER. HUN & DEBUG r otir machms otS« prcgrama independently of Banc
commini* 3K-MC resides m RAM, and Inayns yQU 12V;K of memory to work
with
■ SAVE A LOAD your mtofttr* sod* programs AT DOUBLE SPEED Ai liiil you
fun Heed from Btonnc, your M/dn array&or REM I mas
■ REGISTERS DISPLAY A BREAKPOINTS in make de-buggm-g easier- PLUS
many morv uwlul commands
■ A MUST FOR BEGINNERS * ADVANCED USERS FpU on your
M/C programs, not on howftnd where 10 srore them
• ZIMC is supplied on a hign quality cfcSsetTa, *nh a 3fl page oparaHr»oiniariii#*l.
rTCA Ind VAT&P+P
fC.WQl
SCREEN KIT 1
JUItB of mjicUme- COIte routines for use in Hum<: [sroLjiama. 10
enhance your screen display, and create DATA FILES- on csss<ti«.
Scf sen Km becomes part ol ydu f B asic program
ATA FILES Savt & Load, at double. SpMCl. |usi ihe Basic variables Load
different variable* mm the sama p*ogfam. or eietharwje variables between
programs
■ DRAW A BORDER • KEYBOARD SCAN . HASHING CUFSOR
• CLEAR PART OF SCREEN* LOAO ANV CHARACTER TO WHOLE SCREEN
• INVERTVIDEOOFPARTOFSCflEEN •MEMOflVLEFT
• CLEAR SCREEN BY SCROLLING UP DOWN LEFTOH RIGHT
• Supplied on cassetto »i|h uisiruciions
fR-70 '"' :l VAf !|P * f '
ICWO)
Send laijje 5AE. (or more details Program* available mani order unly
ABO* up to 14 days delivery. Please n/rakfl cheques- PO payable to.
I
6 CORKSCREW HILL. WEST WlCKHAM KENT BR4 &SB
JRS SOFTWARE
19 WAYSIDE AVENUE, WORTHING, SUSSEX, HN13 3JU
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t35 ($09.95}
ft-vi ii.; fi". ibbl^iiI
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tCHDi I <**■-
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L
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to n«iii-i nd ■*
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."i$fiPr-l "' '<un*j Iftv
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I li, I r.H, «,, nufh|Mi i;l hurt inu *£*f m i hi-*!!-"*
' ■'I'uriF
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CH-i^nJ I ±M' ■■• ■■■■ rn-M |..<kiitiin in
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f U> I^IUM Mm m rani H*ihjT LnVkHMt* m l*ii
Xl4 iii.i
ALL FOR ONLY 15.9$ (411.90)
4*Hkf*iH4 -Mnui lik#n MSI
uiui ■ i-i. ■■ |
III 1
Jlt-
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ii ,. |N
■ i .',
SINCLAIR USER May 1982
39
MICRO GEN QUALITY PRODUCTS
ZX81 A/D CONVERTER BOARD
1
This 4 channel analogue to digital converter, originally developed for joystick control, can be used for such applications as
measurement of voltage, temperature, light intensity etc
The board fits in between the RAM pack and the ZX81 (No skill is required to make this connection, and it actually improves the
stability of the H AM pack.) Price now onlv f 1 B.50
JOYSTICKS FOR THE ZX81. only £950 each
* The most exciting add-on ever for the ZX81 . free yourself of that dead., unresponsive keyboard
* 1 or 2 joy sticks may be connected via our A/D board.
* Turns your ZX81 into a true programmable games machine
* Extends the capability of the ZX81. imagine the tremendous variety of games and applications that now become possible
* Details supplied on how to use the joysticks in your own programs
Please note that you cannot connect conventional analogue joysticks directly to the digital input ports found on most I/O boards, an
A/'B converter such as ours is required,
A free copy of 2X AM AZE plus any one of the games listed below when ordering a Joystick and an A/D board
Programs available
You've tried the rest, now try the BEST.
"his program has many features including an ever increasing rate of play, (they'll get you in the end). only f 3. 95
ZX SPACE INVAOERS
Quite simply the best breakout on the market.
"eatures sevwi bat angies. (you won't find this one easy},
ZX NEW YORK
now only C 3 95
A very addictive arcade game
Jomb and shoot you way out of trouble, otherwise you are doomed to crash. Generates a different pattern, fora different game @ach
nme you play . On the reverse of the cassette is ZX R E FLEX, find out how fast you really are. now only £3.95
ZX CHESS
The original and still the best, * Graphic display of chessboard. " 6 levels of play ' Displays record of your moves
and the computers. " Board can be set up to any position. " Has ability to change sides or level m mid-game. * PLUS * CHESS
CLOCK on reverse side, records time taken by each player. * Resetablefunction. "Single key entry. nOWOnlv£6 BO
All our games are written in machine code, and can be used with joysticks or keyboard, (except chess, keyboard onlyi Supplied on
casset te w i t h I ibr a ry cas e
Too allow you to prove to yourself that our products are second to none, MICRO GEN offers the following terms to our customers
14 DAYS FREE APPROVAL ON ALL PRODUCTS
All money will refunded if goods are returned in good condition within 1 4 days of despatch.
If you write a program which is exceptional, please submit it to us We will offer a royalty if it is suitable. Cheques and PO's payable to
MICRO GEN. Dept. SU1 24 Agar Crescent. Bracknell. Berks Please add 40p p&p to all orders
ZX 81 IK GAMES FOR ADULTS
in the Geronimo Pratt Series
Album I "The Adventures of Geronimo Pratt" 8 flicker free
moving graphics programs in which, among other things.
you must:
- help 6.P. keep the repair bills down as he drives Uncle
Gives new Porche
- help him pay those repair bills as he gets a job as a
human cannonball
- help him crack the code of the combination lock on the
bedroom door and. when successful find his true love
inside- with inevitable results! I
Album II "Pra itemization"
Its Party Time with Pratt! I
A multi-player album to try out on your friends at your next
party. See if they are:
. - Sober enough to match G.P. at symbols
-Sharp-eyed enough to Clone-a-Pratt
- or will they Lose their Shirts Bruce Racing?
Whichever program of the 8 on this album you try them on,
they will need nimble fingers and sharp wits. Most games
on this album may alsobe playedsolo against the machine.
Coming soon - "Junior Geronimo"' - an album based on
the best from both adult albums but now suitable for ages
7 id 1 5.
Album) £3 50
Album 1 1 £4 00 Both albums for E7.00
— - Send crossed cheque/PO to:
IBESBFturre*
390/392 Holcombe Road. Helmshore,
Rossendale. LancsBB4 4NF,
Tel:0706 220596
ePS
MOVING AHEAD
WITH
ZX SOFTWARE
ZX CHESS & ADVENTURES
PROGRAMS FOR THE ZX81/SQ INCIUD1NG-
ZX CHESS I
reduced tof 6. 50
Very popular mactirne cod* program, wiih si* levels of
play and arvanalysufjpnon, Unbeaten excapi by
ZX CHESS II
now only €12 99
ADVENTURES
ADVENTURE A'
E6.00
ADVENTURE
E70G
B
A now improver! version nulltl a iasier rnipnrm nmfl.
jsven levels rjf play, and in addition a recommended
move oplton
E<olir>g machine code g#rn#5 W 'th inalent response.
c hcose from i h* rang* fcwlcw. You find yourself stranded
o*t m after) plana*
Can you reach your ship and escape t
In n jungle clearing you came acquis an \m,* 1 ample
You must break in, collar i treasury and en-apa alive
Beware Includes a c astcHcua ve f ou tine
ADVENTURE C" You are unfurl urwtn enough to be drawn 10 an alien
£ 8.00 cruiwr Can you reach Iris central roam and (rue ycmrwH
or will I hey get you first?
Includes a cassette savu muiinr
GALAXV WARRIOR £3.00
Faal and eliciting interac live ernmaiatf graphics geme.
Hum Ctiritfmiiitnd gsihrough black holes
IK GAMES PACK £6 00
GALAXI ANS AM ih* r^ur** u1 rfm arcade game m a fast machine
EG 50 Pojd* pr<jsjrrjm Swooping aitackers. enflkrertMis and
personalised scoring.
4 30 m 1 machtne cods tool and diuswnMn. allow*
access to all registers and id search ihmugh and modily
memory, vvilh cassette, routine!
anri many mrjre For a catalogue giving full derail* v\r?.i?.r. »rrni a S A F \o
ZXBUG
£7 00
Artie Computing
396 James Reckitt Avenue
HullHUSOJA.
I
40
SINCLAIR USER May 1982
^
*
ZX8T PERSONAL BANKING SYSTEM
WITH LOAD/SAVE DATAFILES
ATDOUBLESPEED
Load the program in the normal way - enter amend or delete
your transactions {ZXS 1 will automatically scan standing order
file and post any items due) -save the file of data onto cassette
in 45 seconds - load different datable into the same program,
also in 45 seconds - enter itams, etc - save datable only onio
cassette (45 seconds) - repeat operation for any number of
accounts Idatafilest
Absolutely no need to save program, as all information is held
in datafiles, a powerful search facility is included Very easy to
use - unlike other bank accounts. Requires a minimum of 1 6K
RAM - can use much more (no modification required): on
demonstration at next ZX Microfair (No. 3)
Send £9-95 inc. to J. P Gibbons A IB r for cassette and users
1 4 Avalon Road. manual
Orpington,
Kent,
BR6 9AX
There are only two suppliers of supported ZXS 1 software, this
is one ol them.
(sand large S. A. E.
for details)
Coming soon: Bank Reconciliation Module - a separate
program on cassette that utilises data
supplied by the main program (S.A.E, for full
details) - the only expandable system for the
ZX81
The Personal Banking System is also available from the Buffer
Shop, Streatham, London and Branches of the Computer
Bookshop Group, full maintenance still available.
NEW ZX81
16K SOFTWARE
The Diggles Kitchen
Recipe Cassettes
Celebration dinners to
simple suppers
Volume! 50 pages world wide
recipes £4-99 (inc. P&Pand VAT)
Volume 2 50 pages European
recipes £4.99 (inc. P&P and VAT)
Special price for two volumes
£9 (inc. P&PandVAT)
More volu mes to follow
Please specify which vol Limc(s>- Mail order only
Send remittance to-
MICRO COMPUTER SOFTWARE
Unit D6 r Pear Industrial Estate,
Stockport Road, Lower Bredbury,
Stockport SK6 2BP
Teh 061 -494 2441
Occasionally during the life of a M icro a program is
written that can go on tobecome a standard. ZXS 1
MONOPOLY could be such a program. Most
computer simulations are solitary affairs using a
program that caters only for one ortwo players
ZX81 MONOPOLY allows six players to compete
with the machine doing all the boring bits r actingas
board, rule-book, u mpire. dice -thrower and
accountant. No cheating is allowed and when
required a list of a players properties and the
development situation for each can be listed No
need to worry about missing the rent either,
your ZXS 1 is also trained as a rent collector. The
program is well driven by a clear M END at the start
of each players turn and after the dice hasbeen
thrown. 2X8 1 MONOPOLY also allows the game to
be SAVED with a WINNER so far report. The
program requires 16K RAM and comes complete
with instructions. Let all your friends and family
appreciate the ability of your ZXS 1 NOW
ZX81 MONOPOLY for 16K at £8.00 inc VATand
postage. Cash with orderfrom the publishers.
WORK FORCE
140 WILSDEN AVENUE.
LUTON, BEDS LU1 5HR
OvSr-5BE1*iird=fa*C1 OQPfcf"
lIlAMTCfV 2 * hardware and software
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We ora the major US distributor of hardware devices and toft-
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We eon market yo*jr product in ihe United Slates. If you are a
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you, We're particularly interested inr
Intellectual gomes
Relational data bases
Accounting software and other
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COME BY OUR TABLE AT THE 3rd ZX MICRO? AIR and Ml
us about your product Give us a chance lo review it with on
eye to making you a sound royalty offer. At tne soma time,
pick up o copy of our catalog and our Software Author's
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MINDWARE CO.
Products that supplement nature's computer
70 BOSTON POST ROAD
WAYLANO, MA 01778
USA
(Sir) 356-71 75
SINCLAIR USER May 1 882
41
Finding out about
The trig functions on the ZX-81 are generally regarded as the
least used on the machine. Here Ian Stewart looks into the
mysteries of SIN, COS and TAN
MY DICTIONARY claims lhal
SIN is moral depravity, COS
a curly variety of lettuce and
TAN a colour caused by exposure to
sun. I can imagine computer pro-
grammers engaging in acts of
depravity with a lettuce on the Costa
de Sol but I doubt if they would
admit to it underneath the Q, W, E
keys of a ZX-61 keyboard. So that is
not the explanation.
They are, of course, FUNCTION
keys, What is a function? It is some-
thing to which you give a number
and then it gives you back another
number. Try typing PRINT SIN
1.4423 on your ZX-81 in command
mode — it will print you out a
number, In general, for any number
A, you get back certain numbers SIN
A, COS A and TAN A but for
what are those outlandish things?
A schoolteacher would call them
trigonometric functions, a fussy
word for things used to measure
triangles, Surveyors use them, of
course, but need anyone else bother
with them?
The answer is that they must and
the reason is that they are very wide-
ly applicable Fortunately, you can
learn some of their uses without
undertaking an uninteresting course
in trigonometry.
Radians
SIN, COS and TAN are really
about angles, and angles are funda-
mental beasts. Straightway we hit
the first snag. Sensible people
measure angles in degrees, from
degrees for no angle at all up to 360
degrees for a full circle. You can go
further, say 720 degrees for two full
circle — see example. Then a right
angle is 90 degrees, a straight line
180 degrees, Cut up a square slice of
bread to make two triangular sand-
wiches and the smaller angles are 45
degrees.
Computers and mathematicians
prefer not to measure angles in that
way; their favourite unit is the
radian, Draw a circle of unit radius;
measure unit distance round the
edge; that gives you angle of 1
radian.
mode; if you type P followed by J the
computer will not understand III
denotes space].
10 PRINT " {] [j |j |j DEGREES || [[
RADIANS"
ZOPRINT
30 FOR X =0 TO 90 STEP 5
40 PRINT TA B 4; X; TA B 1 3;
X*PI/18Q
50 NEXT X
10 PRINT" [| [] [j [] RADIANS [| I]
DEGREES"
20 PRINT
30 FOR Y = ID 1.8 STEP I
40 PRINT TAB 4; Y; TAB 1 3; Y" 1 HO/PI
50 NEXT Y
Right-angled triangles
Given h right-angled triangle with
an angle A, name the three sides like
this:
I will not go into the reasons why
this is a good idea but the point is
that you must be able to convert
From degrees to radians or back
again, to make use of SIN, COS and
TAN, The crucial gadget to do it is
the number
PI =3. 14 159265358..,
whk;h is the distance half-way
round the edge of the circle. So 180
degrees — the angle half-way round
the full 360 degrees— must be PI
radians. In Consequence
To convert degrees to radians,
multiply by P1718G\
To convert radians to degrees,
multiply by 180/P1,
Here are two programs which will
illustrate how this works— type
them into your ZX-81 and run them.
Note that "PI" is key M in function
More formal terms are opposite for
vertical, adjacent fur horizontal and
hypotenuse for slanting, Then, when
the angle A is measured, we have:
SIN A = vertical/slanting.
COS A = horizontal/slanting.
TAN A = vertical/horizontal.
So if we know two of the sides anil
the angle A, we can determine the
other side.
For instance, suppose I stand 100
metres away from Nelson's Column
and measure the angle to the top at
73 degrees. How high is the column?
f can lin u ed hit pay •
42
SINCLAIR USER MoylW)2
SIN, COS and TAN
; -Ji
SINCLAIR USER May 1983
t9
k m(^
(continued from page 42)
We know the horizontal and we
want t he vert icah so we have to use
TAN A - verticakhortzontal.
So
vertical = horizontal x TAN A
= 100 x TAN 73°
We have to use radians,
remember? Now 73 degrees is
73*PUl80 radians. So we can find
the answer by using the ZX-B1 in
command mode. Just type
PRINT ]00*TAN(73*PI/IBO).
Do not forget that TAN is key E in
function mode, not T-A-N. You
should obtain the answer
327.0B526,
For some problems like this, you
will need SIN or COS instead. For
instance, to find the distance
between you and the top of Nelson's
Column, you need
PRINT lD0/COS{73*Pl>iarj)
which is
342.03036,
Circles
Circles ere what SIN. COS and
TAN mean but it is not the way in
which they tend to be used in pro-
grams, Try this program:
10FGRY=0TO360STEPi0
20LETX = Y*PI/180
30 LET A = 30+20*COS X
40LETB = 20+20*SINX
50 PLOT A, B
60 NEXT Y
What have you? It is a circle. It is a
trifle bent because of the coarseness
of ZX-81 graphics. The 30s and 20s in
lines 30 and 40 are cooked' up to get
the size and position correct. The
centre is at [30. 20] and the radius is
20, Try varying those numbers and
see what happens. Change the pro-
gram a little and you can plot spirals:
* ^ ^^ ■*.
1
*
\
/
/
t
V
\
V
1
1
\ * \
1
1
\
I
\ 1
/
1
V
\
> mm <*
i
/
\
V
-^ '
/
/
.
10FORY=QTO720STEPl0
20LETX = Y*FI/1B0
30LETR = l.5*X
40LETA=30+R*COSX
50LETB = 20+R*SINX
60 PLOT A, B
70 NEXT Y
Or you can draw rosettes; just
change lines lOand 3Qtu
10 = FOR Y = TO 360 STEP 5
30LETR = 20*SIN(3*X)
and run. Or change 3*X in line 30 to
4=X.5*X.6*X t 7*X...
There are many other uses. In the
program Sink the fcfismorck in my
book with Robin [ones— PEEK,
POKE, BYTE & RAMI— we use SIN
and COS to calculate the trajectory
of a shell fired at a ship,
To end, here are the makings of a
kind of roulette game with letters.
There are some useful ideas in the
program which should have plenty
of applications.
Rouletters [©Ian Stewart 19fi2)
[RunsonlK.ZX-Bl].
10LETC =
2QLETD=100*RND
30LETQ=;17
40FORl = lTO25
50GGSUBZO0
60 NEXT I
70 LET Q= 165
80GOSUB200
90FORT=1T05
100NEXTT
L101FC.> D THEN STOP
120LETQ=37
130GOSUB230
1 40 LET I = 1+1
1501FI>26THENLETI=1
160LETC = C+1
170 GOTO 70
200LETX = rPT/13
210LETA=10+10*SINX
220LETB = 16+10*COSX
230 PRINT AT A, R:CHRS (l+OJ
240 RETURN
• Ian Stewart is a lecturer in mathe-
matics at Warwick University, the
author of 20 hooks, including
Concepts of Modern Molhemotics.
Get Knotted.' and — jointly with
Robin |ones— PEEK. POKE, BYTE &
RAM! — Basic; Programming for the
ZX-81.
44
SINCLAIR USER May 1B82
.
•
SINCLAIR USER
- the best
enhancement yet
for the ZX enthusiast.
Make sure you get it monthly!
What is the best way to guarantee (hat you
never become bored with your Sinclair
computer?
The answer is to subscribe to Sinclair User ... written
specifically for owners of ZX 8£fs and ZX 81's. Sincl..ni
User is the latest monthly from ECC Publications ■
pioneers of Practical Computing, WHICH COMPUTER?
and Computer & Video Games. Whether you bought
your system yesterday or are an old hand, you are
probably an enthussa&t for your machine. And your
biggest problem is likely to be obtaining all the
information to satisfy your interest We promise that
Sinclair User will be devoted entirely to quenching your
thirst for information.
As the name suggests, the content will be geared
specifically to helping you, the user. There will be pages
of information on available hardware and software. Our
expert writers will analyse established products to help
you make The right choice. There will be exclusive pre
release snippets on products which are about to hil the
market. Our aim is to make Sinclair User invaluable and
we will chronicle applications which are of special interest
Each month we will carry pages of programs. Another
mu si for every user is our first-rate helpline service And
we intend to carry as much information as possible
about clubs. Last but not least let us say that the best
way you can guarantee you like the magazine is by
participating yourself. Don't forget to ask us your
queries; send in your programs for which we will pay
£10 if we publish and be sure to tell us if you are using
your ZX 81 in a special way. Send in your club news
and tell us of any interesting people out there in
userland. And jusi in case you need luriher conuim ing,
look at our forthcoming editorial plans.
Can you continue to get the most out of your ZX
without reading the Sinclair User every month? So why
not fill in the subscription order form today?
Editorial Plans
May
1>w Sinclair 1«< RAM
Hiss,'-
■ hit*;, programs
June
S>ml<t a. look. IHH> frit 1
future
Graphics 5t1JtwJTlL■
July
The ZXB1 memmry map
.utilised
[>bu<jgin3 programs
•
*•
X
August
Tk' Sinclair printer
and ii* aliematiwes
Chess programs
September
Erihu t iLWH g U* (of ihe enthuswuJ ^,&
Ifj cofour. sewnd, f ^
Business sofiware - ,-F jd?
br ihe £JCS1 W If ' jfE* s&>
ECC PUBLICATIONS
30/31 ISLINGTON GREEN LONDON N1 &BJ
SINCLAIR USER MoylMS^
45
Sinclair ZX81 Personal Com
the heart of a system
that grows with you.
1980 saw a genuine breakthrough -
the Sinclair ZX80, world's first com-
plete personal computer for under
£100. Not surprisingly, over 50.000
were sold.
In March 1981, the Sinclair iead
increased dramatically. For just
£69 95 the Sinclair 2X81 offers even
more advanced facilities at an even
lower price. Initially, even we were
surprised by the demand - over
50,000 in the first 3 months!
Today, the Sinclair ZX81 is the
heart of a computer system. You can
add16-times more memory with the
ZX RAM pack. The ZX Printer offers
an unbeatable combination of
performance and price. And the ZX
Software library is growing every day.
Lower price: higher capability
With theZX81, it's still very simple to
teach yourself computing, but the
ZX81 packs even greater working
capability than the ZX80.
It uses the same microprocessor,
but incorporates a new, more power-
ful 8K BASIC ROM -the "trained
intelligence' of the computer. This
chip works in decimals, handles logs
and trig, allows you to plot graphs,
and builds up animated displays.
And the ZX81 incorporates other
operation refinements - the facility
to load and save named programs
on cassette, for example, and to
drive the new ZX Printer.
BASIC manual
Kit:
£49.
95
f very ZXB1 Camas vrtlh a comprehensive, speciall y - wrrlten
manual - & complete Course iri BASIC programming,. Irpm
first principles lo complex programs.
Higher specification, lower price -
how's it done?
Quite simply, by design. The ZX80
reduced the chips in a working
computer from 40 or so, to 21. The
ZX81 reduces the 21 to 4!
The secret lies in a totally new
master chip. Designed by Sinclair
and custom-built in Britain, this
unique chip replaces 18 chips from
theZXSO!
New, improved specification
• Z80A micro-processor - new
faster version of the famous Z80
chip, widely recognised as the best
ever made
• Unique 'one-touch 1 keyword
entry; the 2X81 eliminates a great
deal of tiresome typing. Key words
(RUN, LIST, PRINT, etc.) have their
own single-key entry.
• Unique syntax -check and report
codes identify programming errors
immediately.
• Full range of mathematical and
scientific functions accurate to eight
decimal places.
• Graph-drawing and animated-
display facilities.
• Multi-dimensional string and
numerical arrays.
• Up to 26 FOR/NEXT loops.
• Randomise function -useful for
games as well as serious applications.
• Cassette LOAD and SAVE with
named programs.
• 1K-byte RAM expandable to 16K
bytes with Sinclair RAM pack.
• Able to drive the new Sinclair
printer.
• Advanced 4-chip design: micro-
processor, ROM. RAM, plus master
chip - unique, custom-built chip
replacing 18ZX80 chips.
Built:
Kit or buitt - it's up to you!
You'll be surprised how easy the
ZX81 kit is to build: just four chips to
assemble (plus, of course the other
discrete components) -a few hours'
work with a fine-tipped soldering iro n,
And you may already have a suitable
mains adaptor - 600 m A at 9 V DC
nominal unregulated (supplied with
built version).
Kit and built versions come com -
piete with all leads to connect to
your TV (colour or black and white)
and cassette recorder.
16K-byte RAM
pack for massive
add-on memory.
Designed as a complete module to
fit you r SinciairZX80 or ZX81, the
RAM pack simply plugs into the
existing expansion port at the rear
of the computer to multiply your
data/program storage by 16!
Use it for long and complex
programs or as a personal database.
Yet it costs as little as half the price
of com petitive additional memory.
With the RAM pack, you can
also run some of the more sophisti-
cated ZX Software - the Business &.
Household management systems
for example.
the ZX Printer
for only £49.' 5
Designed exclusively for use with
the ZXS1 (and ZX80 with 8K BASIC
ROM) , the pri nter offers full alpha-
numerics and highly sophisticated
graphics..
A special feature is COPY, which
prints out exactly what is on the
whole TV screen without the need
for further intructions.
At last you can have a hard copy
of your program listings -particularly
useful when writing or editing
programs.
And of course you can print out
your results for permanent records
or sending to a friend.
Printing speed is 50 characters
per second, with 32 characters per
line and 9 lines per vertical inch.
The ZX Printer connects to the rear
of your computer - using a stackable
connector so you can plug in a RAM
pack as well. A roll of paper (65 ft
long x 4 in wide) is supplied, along
with full instructions,
How to order your ZX 81
BY PHONE -Access, Barclay card or
Trustcard holders can call
01-200 0200 for personal attention
24 hours a day. every day.
BY FREEPOST - use the no-stamp-
needed coupon below You can pay
by cheque, postal order, Access,
Barclaycard or Trustcard.
EITHER WAY - please allow up to
28 days for delivery And there's a
14 -day money-back option. We want
you to be satisfied beyond doubt -
and we have no doubt that you will be.
To: Sinclair Research, FREEPOST, Cembertey. Surrey. GU15 3BR.
Order
■ ■ ■
indaii—
ZX8I
6 King* Parade, Cambridge, Cambs.. C82 1SN
Tel: (0276J 66104 & 21 282,
Qt*
Item
Coda
Item price
Total
£
SinclairZXfll Personal Computer kit(s)- Price Includes
ZXfll BASIC manual, excludes mains adaptor
12
49.95
R eady -assembled S i ncl a i r ZXB1 Personal Co rnpu ter(s) ,
Price Includes ZXS1 BASIC manual and mains adaptor,
11
09.99
Mains Adaptor(5> (600 mA at 9 V DC nominal unregulated)
10
a.95
16K-BYTE RAM pack .
IS
49.95
Sinclair ZX Printer.
27
49.95
SK BASIC RO M to fit ZXSO.
17
1995
Post and Packing.
295
n
i
□ Please tick it you require a VAT receipt TOTAL £
*l enclose a cheque/postal order payable to Sinclair Research Ltd, tor £ —
•Please charge to my Access/Barclaycard/Trustcard account no.
•Please cielBtoj'cDmplftls as actHtcaWe, I J I J_ — I 1 1 1 1 1 — 1— J 1 —
pnnl
Name: Mr/MrsJMiss
Address: I — I — I — L
I I I
I I I
I I I
LA.
' I >
I
I I I l
I I I
I I I M 1 I I I |
FflEEPOST - no stam p needed, sy s ° 5
I LEARNED machine code in the
school of hard knocks, clutching
my Mostek Z-80 programming
manual, which is now very tattered,
and the Nascom-1 documentation,
which was not particularly helpful.
They were heady pioneering days
but this series of articles is designed
to take you through the machine
code hoops, so that your cranium
does not suffer too much pain. It will
start with first principles and
culminate in the production of a
machine code-based game.
Why make the effort to learn
machine code? Three main reasons
spring to mind:
It is faster in operation than the
equivalent Basic program.
It occupies much less Space in the
memory than the equivalent Basic
program- — that is critical on the
unexpended ZX -81.
It gives greater scope for the
imagination than Basic With Basic
you are tied to the menu of instruc-
tions the manufacturer has given
you in the brain — ROM — of the
computer. With machine code, you
can make the operating system do
things outside the set menu, make
the screen scroll printed information
downwards — the Sinclair menu
gives only a scroll up.
So machine code can be packed
tighter, run faster and produce more
imaginative effects outside the
manufacturers original Basic
instruction set.
Machine code is a set of numeric
instructions, called bytes — eight
zeros or ones in any combination —
which, when addressed to the Z-BO
chip centra] processing unit, make it
perform some sensible function. The
Z-BO would not understand a Basic
instruction, such as PRINT, directly.
A very complex piece of machine
code called the Basic Interpreter
breaks PRINT into numeric instruc-
tions for the Z-60 chip to produce
the required effect from the com-
mand PRINT.
Those hexadecimal codes —
number base 16 for convenience-
are listed under Z-80 Assembler in
theZX-8l Manual—pages 181 to 187.
It seems a little daunting but really
the fundamental things you can tell
the Z-80 chip to do are really simple
but the overall effect can be very
powerful
Here is a summary of the main
things you will ask the Z-80 to per-
form during a machine code pro-
gram; you ask it by simply feeding it
the appropriate code.
• Add one to the contents of a regis-
ter — called increment, A register is
somewhere in the chip where you
can hold a numbeWvalue to do some-
thing with it.
• Take one away from the register
— decrement,
• Save the contents of the register
elsewhere, so you can use that regis-
ter for something else — Push.
• Bring back the saved value into
t he regi ster — Pop .
• Carry-out a machine code routine
somewhere else, then return to the
same point in the program— Call
and Return.
• Jump backwards or forwards a
number of instructions if a register
or part of a register is not zero —
Jump Relative No Zero.
• Jump backwards of forwards a
number of instructions if a register
or part of a register is zero — Jump
Relative Zero.
• Load registers with specific
numbers.
They do not appear to be the build-
ing bricks of computing power, but
they are.
To put machine code into a ZX-B1,
write a single-byte instruction to an
address in the memory. The POKE
instruction takes the general form:
POKE 16514,12
Address Instruction Code
The POKE instruction operates on
decimal numbers, so that all the
hexadecimal codes must first be
converted to decimal before POKE-
ing them into the computer memory.
The decimal code 12 instructs the
Z-80 chip to increment — add one —
to its 'C register.
The most suitable place for the
code, it is generally agreed, is within
a REM statement placed at line 1 of
the program. The machine code
loader — figure one — POKE your
machine code into spaces after the
REM statement — addresses 16514
onwards.
Easy to ai
powerful
Mike Biddell begins
a series of articles
aimed at explain-
ing — in the simplest
48
SINCLAIR USER Ma y 1082
machine
code
issemble
il bricks
possible terms — the
advantages of pro-
gramming in ma-
chine code.
So sit at your ZX-81 keyboard,
switch on and type it in. There are
approximately 100 letter Ms after
the REM statement, to reserve space
for machine code-
When the program is in. run it t
then type POKE 16514, 128; do not
use a line number — this is called
POKE IMMEDlATE^and remem-
ber that POKE is entered by pressing
the letter O key once. What you then
see is that the first letter M after the
REM statement has changed to a
black square. The reason is thai
although 128 is the Z-flO op. code for
adding the contents of the A end B
registers in the Z-80 chip, it is also
the ZX-81 character code for a black
square.
The computer tries to display arty
number POKEd into the display file.
Then try t he following:
POKE 16514,124
The black square will have
vanished and a question mark is
displayed. That is because code 124
is not a character code, so the com-
puter displays a question mark
instead. Then we can enter our first
machine code program but previous-
ly we call a machine code program,
using the USR function and the Basic
statement as follows:
e.g.lOLETA = USR(l6514]
That tells the program flow to
jump to and execute the machine
code routine, starting at address
16514. An additional piece of infor-
mation which can often be used to
advantage is that the value given to
A is the same as that contained in the
B and C registers, combined, of the
Z-80 chop.
To get back from machine code
routine you must end the routine
with the cade for RETURN— Le..
201 . Then enter the following simple
program, using t he loader:
Decimal
1
1
201
Namonic
LDBC.01
RET
Commant
Load the SC register
pair witti the Value 1
Return lo the Basic
pragranlrna
Run the machine code loader then
enter I Newline, 1 Newline, New-
line, followed by 201 Newline. You
will then see in the REM statement
two small blank squares, followed by
a space, followed by TAN — ell is
then well.
Then delete lines 4, 5, 20, 30, 40
and 50 from the program and add
lines 3, 10 and 30 — figure two.
If you then run the program
shown in figure two. r figure 1 will
appear on the screen. That shows
that your first machine code
program has run correctly. You have
loaded the BC register pair with the
value one, the program has relumed
from machine code to Basic success-
fully end printed the value of A,
which is the value contained in the B
and C registers as a pair.
Those then, are the rudiments of
machine code writing for the ZX-81
and from these humble beginnings
much can be developed.
Figure J .
± REM MMMMMMMMMMMMMMMMMMMMMMK
MMMMMMrtHMMMMMMMMMMMMMMMMMMMMMMMM
HHMHMMrtMMMMMMHMHMMKMHMMMHrtWMMMMM
MHHMM
3 LET T = 1651d.
4 CI-3
5 LIST 1
2Q INPUT C
3© POKE T,C
40 LET T=T+1
5G5 GOTO 4-
Figure 2.
1 REM ■■ TftN H«MMMMMMHHHHMMf»<
MMM^tH^rhr^^^^HHHM^^h^^^^»^!^THHH^tHHhihr^rM^I^TN
MMMMMMMMMHMHMMNMMMMMMMMMMHhTMMHMM
MMMMMMHM
3 LET T=16SI4
1© LET fi=U5R (T)
20 PRINT ft
SINCLAIR USER May 19B2
49
What to
Don't panic! Here is the Sinclair User beginners* guide
ZXeiZX81ZX81ZXS1ZX81ZXBlZX8lZX81ZX8lZX81ZX81ZX81ZXaiZX81ZX81ZXB1ZX81ZX81ZX81ZX81ZXB1ZXS1ZX81ZX8l2>8
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SO YOU have taken the plunge
and bought your ZX-61 — now
what? You may have a
specific use for the machine in
mind or you may simply be
fasci nated by the prospect of own-
ing your own computer and keen
to learn more about it. Here art? a
few general hints to help you.
Don't panic
If all you know about com-
puters so far is that they usually
try to take over the world in
science fiction films, do no!
worry. The ZX-81 was designed
for you. You do not have to be h
genius or a mathematical wizard
to use it. This compute? was made
with the beginner in mind and
will lei you learn in easy stages
and take you on to advanced
computing.
The ZX-81 is fairly robust and
tolerant of mistakes, so nothing
you do to it in ordinary use will
cause any damage to it, or to your
television or cassette recorder.
You can enter anything you like
from the keyboard; it will not
necessarily work but it certainly
will do no harm, If the worst
happens and you find strange
pictures on the screens, or the
keyboard will not respond, you
pull out the power plug, wait for a
second or two, plug it back and
your machine is as good as new.
Remember only to do that as a
last resort, because you will lose
everything you have typed-in.
The programs you put in will stay
thereonlywhilethepowerison
Setting up
The instructions for setting-up
your computer on page seven of
the manual are reasonably
comprehensive and you should
normally have no problems. It is
worth checking, if you have just
opened the box. to moke sure you
have all the correct pieces — a
ZX-Bi, a power supply unit> a
manual, an aerial lead and a pair
of cassette leads. Connect up, turn
on the power — remembering to
keep the TV volume low to save
your eardrums — and tune to
channel 36UHF, You may have
slighi difficult]/ locating the UHK
tuner on your TV because some
manufacturers manage to con-
ceal it fairly skilfully. If you have
a push-button rnndel, switch to an
unused channel and turn the push
button.
On other models the tuner is at
the back of the set or sometimes in
a pull-out tray at the Front. Once
you have tuned-in, you should see
a black square in the corner of the
screen with a white 'K' like the
picture in the manual. If the K'
does not appear, double-check
thai you have everything
plugged -in to the correct sockets
and that power is on, then re-set
the machine by unplugging the
power for a second or SO and try
tuning again.
The 'K" will take fractionally
longer to appear if you havealBK
memory connected. If the picture
remains fuzzy or unsteady you
may need to adjust the vertical or
horizontal hold on the TV and
check the aerial lead for loose
connections. If all that fails. Iry
another set before you send for a
replacement-
It can save family arguments if
you can afford a separate TV for
your ZX-81 : you can buy a cheap
portable set for around £50 or
obtain a second-hand one even
more cheaply. Similarly, it makes
life easier if you can find a corner
somewhere to leave your equip-
ment permanently set up —
unplugged. You will find that you
use a few power sockets for your
system and a four-way block con-
nector on a short length of exten-
sion cable helps to tidy trailing
leads,
Talking lo your ZX-81
The ZX-81, like a pocket calcu-
lator, 'understands" numbers and
signs like plus and minus. It is far
more sophisticated, however,
than a calculator and can also
cope with letters and words —
I hose on the keyboard — provided
they are presented in the proper
way.
A calculator follows the rules of
arithemtic; the ZX-fll uses an
artificial language designed for
8lZX8lZX81ZX81ZX81ZX81ZX8lZX8lZX8lZXaiZX81ZX81ZX81ZX81ZX81ZX81ZXS1ZXB1ZX81ZX81ZX81ZX8lZX8lZX8lZ!8
50
SINCLAIR USKR May t932
start in
from scratc
BtZ> fi1ZX81ZX81ZX81iXB1
-
computers, called Basic. There are
many computer languages but
Basic is a good genera I -purpose
one, fairly easy for non-computer
specialists to learn and found
widely on microcomputers.
Most manufacturers have their
awn slightly different version or
dialect of Basic and Sinclair is no
exception. What this means, in
practice, is that a program — e
series of instructions to the com-
puter — written for one machine
will not work on another without
some modification but if you
understand Sinclair Basic you can
soon learn the minor peculiarities
of other versions and. with a little
practice, adapt them for the
ZXhBI.
You do not need to wait to learn
the language to start- You can
copy the programs you find in
Sinclair User. A word of warning.
Make sure you copy them exactly.
You may understand a sentence
with a comma or a quote omitted
but your ZX-Bl relies on those
cues and the program will not
work wi thout them.
For that reason, it is a good idea
to SAVE a program on cassette
tape before you press RUN and
NEWLINE to make it work. That
way, if you have made a mistake
and you lose the program from
the computer, you can LOAD it
back quickly from the tape and
look for the error, without having
to type it in from the beginning.
'ZX8lZXB1ZXaiZX81ZXeiZXaiZX81ZXB1ZX81ZXaiZXB1ZXB1
zx
81
zx
instructions you have typed -in as Bl
a coded sound signal whicih you * x
can record on to ordinary cassette zx
tape. When you want to use the B1
program you play it back to the | x
ZX-fil and il translates the coded ZX
sound back as your program *\
To rec o r d a pr eg r a m , y ou S A VE at
it and to play il back you LOAD it. zx
Chapter 16 of the manuals tells *J
you in detail how to do it. You si
may have problems occasionally zx
in LOADing, usually with tapes |J
recorded by other people. One ai
way to deal with that is to wind ^ x
the tape to the middle of the pro- ;x
You can also buy a wide variety
of commercially -produced, pre-
recorded programs on cassette.
They can vary a good deal in
quality and yovi will need to read
the reviews and use your
judgment to choose the best,
A good deal of the interest and
fun of having your own computer
is in writing your own programs,
which is easily as fascinating as
playing even the best game of
Space in voders written by some-
one else. The manual deals
thoroughly with Sinclair Basic
hut if you find it heavy going or
not to your taste, there are plenty
of hooks available for the ZX-fll,
Check your local bookshop and
find one which suits you.
Many people feel that the best
way to learn is to plunge in at the
deep end and see what you can
make the computer do, Refer to
the manual if you have difficul-
ties. You can ignore the functions
and calculations initially and
Hxperimenl with PRINT state-
ments to get the feel of your
machine. The beauty of having
your own computer is that you
can learn at your own pace in the
style which suits you best.
Keeping your programs
You lose the program contents
of your computer when you turn
off the power but you can take a
copy of the program, because
the ZX-B1 can reproduce the
gram Slid type LOAD" " followed 81
by NEWLINE, then slowly turn * x
up the volume of the recorder zx
with the tape running until the 81
television screen shows four or 81
five horizontal black bands. If you zx
then re-wind the tape, the pro- 81
gram should load normally at the 81
volume setting, ZX
81
ZX
Carry on computing B1
Finally, a health warning. Apart zx
from any practical uses, comput- *i
ing with your ZX-fll can be a very 81
entertaining hobby and is almost * x
certainly habit-forming. You mav zx
easily find yourself crouched 8i
over your machine, red-eyed, in **
the early hours of the morning, zx
thinking that in another five ai
minutes you will sort out the Z*
problem. Try to break that habit zx
by getting into the fresh air and 81
meeting other Sinclair users; it B1
undoubtedly will help your pro- zx
gramming — and your non-eom- |1
puting friends, poor souls, will fl i
probably be sick to death of hear- zx
ing about computers by that time *x
inanycase. ei
By getting a ZX^Bl you will fi rid | x
you have joined a not very exclu- zx
si ve club with many thousands of 81
members, many of whom would | x
be only too happy to advise you if zx
you have problems. Sinclair User 81
will help you to get in touch with | x
other users by printing a list of zx
clubs each month. 81
<81Z> 8lZX81ZX81ZX8lZX81ZX81ZXaiZX8lZX8lZXB1ZX8lZX8lZXaiZX81ZX8lZXSlZXS1ZXB1ZX8lZX8lZX81ZX81ZX81ZXaiZxai
SINCLAIR USER MaylBB2
51
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Authors:
Ian Stewart & Robin Jones
The reader friendly guide
to getting started with
the Sinclair ZX31.
Includes an intro-
duction to looping and branching,
graphics, subroutines, and debugging techniques, with over
BO programs designed to run on the standard IK memory.
110 pages - Paperback £4.95
ISBN 0906312 178
Published by: Shiva Publishing Ltd. 4, Church Lane,
Nantwich, Cheshire CW5 5RQ, Telephone: <0270) 628272
Order from your bookseller or fill in the coupon
-""P — mr -W IB BBK i— — — — — — __ _ bbh __. .hb.. .- L ^^_. .^^ ^^_ ^_ _
Please supply me with ....... copy/copies of PEEK,POKE,BYTE &
RAM. For 1 St CUss Postage please add 25p
Pric*: £4.95 per copy. Cheques pa v able to Shiva Publishing Ltd.
NAME < Capitals please)
Full Postal address
For payment by Access/ A menca n Express
Card Mo. Signature
Two new games for ZX81 16K
ANAGRAM
Two games
supplied on
one cassette
Price £4.95
O
S
S
W
o
R
D
Crossword is
played on screen
and tests your
knowledge of
ZX81 terminology
Anagram can be
played against the
computer or a
human opponent.
Three levels of
difficulty.
Send cheque or postal order to:
Com puta tutor
3 Thalia Close
Greenwich
SE109NA
52
SINCLAIR USER May 1082
inside
Sinclair
Qntfrfipmriuc
A piece of cake
in Dundee
Lynd Church goes to
just how the ZX-81 is
TN KEEPING with its philosophy
I of sub -contracting all manufac-
turing processes. Sinclair
Research appointed Tim ex to pro-
duce the ZX-81 when it was intro-
duced in March, 1981.
Since thai time, production at the
Tim ex plant at Dundee has
increased from 1 0,000 to 60,000 units
per month, while production of the
Sinclair printer, also in the Timex
factory, is now running at 15,000
units per month,
David Chatten. production con-
troller with Sinclair, explained lhat
although the company does not
undertake its own manufacturing, it
is very thorough in its analysis of
Scotland to discover
manufactured
prospective component manufactur-
ers. "We gel people who are good at
manufacturing particular compon-
ents, then get everything assembled
in a good production plant", he said.
The rate of growth of units pro-
duced at Dundee not only reflects
the success of the ZX-81 but also
justifies Sinclair confidence in
Timex, a company which had little
experience in the assembly of elec-
tronic equipment.
Allan Johnston, project manager
of board assembly at Timex, explain-
ed lhat the company decided to
expand into new technology when
watch technology began to change.
He said: "Our experience at Dundee
was in mechanical watches but
development in quartz and digital
technology led us to consider expan-
sion into other arees".
So Timex and Sinclair began dis-
cussions on the production of the
David Chatten
AQan Johnston
Sinclair flat-screen lube and Micro-
vision pocket TV, for which Sinclair
has announced a £5 million four-
year capital investment programme,
Because Timex had no experience in
electronic assembly, it was decided
that the production of the ZX-fll
would be a first step in the learning
process, added to which Timex was
prepared to make the capital outlay
for equipment needed for such
assembly.
Chatten also stressed that assem-
bly staff at Timex are of very high
calibre, the best of whom were, initi-
ally, taken off-line to train in ZX-81
assembly. Chatten added:
f conlmund un page 54]
SINCLAIR USER Moy1S82
y.i
(continued from page 53} manual assembly. ]t is at that point
"Getting Timex to do the assembly that the first test of the equipment is
on the ZX-fll may have been a risky made.
decision in the short term but in the Bearing in mind that the assembly
long term it provides us with con- process has not then reached the
siderable security, giving us the keyboard stage, the test is to esiab-
Suiltiing up the circuit bonrd
opportunity to build good working
relationships before full production
on the pocket TV begins**.
Whatever the risks, production of
the ZX^Hl seems to be proceeding
smoothly, with only minor difficul-
ties still to be solved, according to
Chatten. The process starts with the
build-up of the printed circuit board,
including the addition of diodes and
resistors. The board then goes
through a flow-solder machine,
lish that the board is alive and well.
It is called the K test, because all it
requires is the appearance of the K
on the screen, notifying the user that
the machine is ready for instruc-
tions.
If a board fails the K test, it is thru
tested on a GenRad 2270 which
Inserting the chips
identifies the Fault and produces a
printout denoting the area at fault.
The printout is then attached to the
board, which is returned to the re-
work section, before going through
the entire process agai □ .
Assuming that the board has
passed the K test, the top half of the
casing with the touch-sensitive key-
board and connectors is assembled.
At that point, the ZX-Bl is again test-
ed, running off a test program on
cassette which will display a series
of OKs on the screen for every key
tested.
Finally, the bottom half of the
rasing is attached and the completed
ZX-eis are packaged for distribu-
tion.
There are three main avenues of
distribution — Jaserve, a fulfilment
house which deals with mail order;
Griffin and George, school suppliers:
and the VV H Smith distribution
After soldering
which solders all the components
into place and includes a cutter to
tidy the leads.
it is only at that point that the
chips are added to the board. They
arrive at the Timex plant in anti-
static tubes and are fed into a slide
dispenser to ease the process of
fast mg .for faults
54
SIMCLAfR USER May 1902
' i
f
centre at Dunstable. Bedfordshire.
Timex has also agreed recently with
Sinclair lo market personal com-
puters, peripherals and software in
Norlh America.
Distribution for them will be
handled by established Timex
shipping agents, distribution net-
work and retail outlets in the U.S.,
though Sinclair will continue to sell
the ZX-81 by mail order from its
Boston -based subsidiary until
Timex sales have reached agreed
targets. At that stage Sinclair will
begin to concentrate on sales of its
yet-to-be-released flat-screen TV.
The machines in North America
will be marketed under both Sinclair
and Timex names and Sinclair will
receive a royally on all sales under
the agreement, which covers, current
and future Sinclair personal com-
puter products and Timex develop-
ments of Sinclair computer tech-
nology.
Timex obviously has a fair amount
of confidence in the product it is
assembling for Sinclair, demonstrat-
ed by its use of the ZX-81 to test the
printed circuit board of the Nimslo
3D camera, assembled by Timex and
soon lobe marketed in the U.S.
AssraiiWfiTS iheknybuurd
Sinclair believes that such con-
fidence is well justified, pointing to
what it considers to be a low percen-
tage of returned equipment. The
return figure on the ZX-81 is 2.4 per-
cent, though the percentage return
on kits is higher, at around 13
percent,
C;hatten claimed thai the higher
figure of kit returns is due more to
poor component insertion and bad
soldering than to component failure
but stressed that if any component
failure is found, the £10 which kit
customers have to pay for a ZX^fll to
be serviced is returned.
He admitted that of the 2.4 percent
returns of supplied ZX-81 s. around
one percent of failure is due lo pm . en
supply faults, an area in which
Chatten believes there could well be
Teslinjj the keyboard
Finished printers
improvement. In fact, it is Clive
Sinclair's stated aim for a return per-
centage of one percent overall and it
is partly to that end that he recently
appointed a quality assurance
manager, David Fuller,
While an aim for continued
improvement in machine reliability
is a necessary part of successful
business practice, the gamble of
engaging a company with little
experience in electronic assembly
seems to be paying-off. Chatten
commented:
"There is some room for improve*
ment in the assembly process —
perhaps greater use of automated
production lines — but on the whole
we are very pleased with Timex
work".
SINCLAIR USfcR May 1982
55
LTEXT AND ZTEXT
ZX81 WORD PROCESSORS
lower case characters
£ ontheZX printer!!
£7 50
for the pair
No lonuer need -v<iu b? <;<inlin,n<J lo space psmaa, baltleships and thr like WMh
ihe»* prognMRt your £XS 1 tetanies a viable commercial machine, jTTEXT (updflr
ctu characters only) and LTEXT (upper anal lower ca$«r Chtractars) are word
processors which rncorucraia a re*1 edi[f>r »n<i ;i lormaitnr/prinler The lem
editor allows you to iyoe [em in anil ruin n Trurformatter/rxmtBr takas. Hie text and
sends n so [ha ■HWfl ar IX prinlnr. justifying H and Formatting acuunlinu in
commands em0^il<li)^ in (tip roxl. Included in the range ot com man H-, ,i-.- '.
useful operations as string search, string replaeenie-m and a mvrps facility
pnqrjlm^ a skeleton document to be filled wirb mttblt information LTEXT
caters 'or both upper and lower case GtoflKttri Ntk [hat is not a. mispfiM By
utilising (lie hpuh resoluiKWi Uraphit* Icftlurg erf the ZX printer Gratia m A&he-r has
buili a compJera set ot lower ^ts» characters These programs come- tomplai*
wiTh a ilei ;ji lr[J m i n ii;< I
Send 95p (redeemable against first order} for fulf catalogue
and FREE listing. Please state ZXS1 on order.
All prices include VATand P&PavailaWe from
Oasis Software. Lower North Street Cheddar, Somerset.
Tel: Cheddar 743409
Dealer enquiries welcome
KMJ.W *l WtHH
nn
i i . i r _ i r *. nu
* i^ uim \t i.sovs is \t> t i ihi * -t nn }\m\s »
+ PRQ\ HYn<)\ ,i
HI t ; <, i ;/r;\ *
if-/ / / J/;/ #.**
Trr ..*njfftu s.
* - ft 1 1 1 \ o/ n i\ *
* s ii/: c.-iw / k ////> .
+ MA.\ 4f;rn i \i k i ft\(, ♦
IC it \t \!( fl * f. I. r f /'*
... is a stylish and
ergonomic plinth for theZXSI. It raises and
t iris the TV to avoid eyestrain, holds the 16K RAM
in place and hides the wiring and power supply.
This very professional unit costs £IS, a built-in
powerswitch is £3, plus postage at £ I. SO. inc. VAT
Peter Furlong Products, 125 Catford Hill. London SE6 4 PR.
Callers by appointment, please Tel 01690 7799. Visa. Access,
mmi m^mmiiiimimnwttttmrYrtiYVWWVNWiittNWi'rtW
thi% ■<. Mil d uuti' simulnliim. I his K un rii-iling and hj^hh rnjittahlr
ftiim* in whith j mi pint tin,' i",irr i>| j hmlhjll Maiiae.iT mpiiiK nil'h (hi
pruhli' mi and divitimii, itmilicd in running mm iluh. I run- aCr mi miini
trailing il i% impiistiblt In IKl Ihrffl hrre bul inilnilvil j.rt tfirm lltip
h.iin, NOHM-\l l.i ninp, ^ijinl -k4Hini>s, wjk* hilk tn pn.uiid \<>u iirfi
fU'fl llr Bitted! II k » gamr requiring a jjreal il*jJ »l vtill. iii.l pvi^ir
pi j i ii for liU'MiU l|unr> im i-nil |CHT bm (jnntKl
W|\ <.l \H \N I H. Ihar lhi\ is <nir ul Hi, ht^l ninipulrr i>jmi< tnu'tr
r»#r ffljitd:
III I Bt \\ \Kt . Ihi> EJinc i> ritri-iiii'k ;ul<lu iiir
hioirm.i m.-\sa(;1'.:k
• PLIED n OH f«K/( t Hi >\ HtHiA
■ occupti . im i \iini fin itt\t
kardwake: hkui IRtU
/\Ki
/.X80
UK HAM
TttS&H
I iiivn livnie
I til I II
";lmrmH'h£(fufflf £F.9$
modrtvyalilr m- ABDtt IM i. bW I
■« iMpti.t'. p.o. *v.k m
wr WW a/ i ^r ^ v«/^ 7\^
I'l I i\l M ill i OMPt ii H
ZX81 with 1 6K RAM-PACK
6 GAMES ON CASSETTE
FOR ONLY £3.50(Postfree)
Not one, not two, but SIX exciting games, an one high-quality
cassette, ready to load on your ZXB1 with add-on 1SK RAM
pack. Ea&y io operate, fun to play' Hours of entertainment for
all thefamilyl Comes with full documentation, games
descriptions and easy-to-follow loading instructions.
• THE MONSTERS F DRA HGO0 L Enter the underground
lab vrtnth of Df argoo I a t y ou r pen I . R is k dea th f ig ht i n g t h e mon^
weird and fierce monsters in yoursearch for trya&ure. Only the
luckiest get their treasure out alive*
• SNAIL RACE Back the snail you fancy in each of four races
- unless you lose you r shirt I Cons ta nt on- sc raen di SpJay
reminds you how much cash you've got, which snail you
backed and at what odds (which vary from race io race and
game to game).
• G U N F I G HT S hoot i t o u t ac ro ss a canyon with three
desperadoes. Get them all before they get you !
• H O U LETT E For s wo plays rs again st t he ZX 8 1 T he classic
c as i no ga m e, wit h eigh I d iff e rent bett i n g opt i ons and s i m u la ted
wheel -spin
• 6 ATT L£ $ H I PS Th e sc h oolboy game trough t up to date
How good a naval gunner will you be?
• ME- AHMED BANDtT Your oiwn 'fruit machine" on the TV
screen "Hold"' facilrtyandconstantly-updated scretan display
of your progress.
All the above games have informative arxJatiractivB screen
d i spla ys wit h none of I he impl e asa n t "screen-flashing ' tha t
s poi Is so me other ZX 8 1 games . G et you r c ass e I te of six ga mes
today 1
SENDTODAY! MONEY BACK I F NOT DELIGHTED!
Price includes cassette, iibrary case, in/ay. documentation
andpostage
Send £3 50 cash/ PO /cheque to.
MOVIEDROMEVIDEO(SUI)
1 9 Leighton Avenue, Pinner HA5 3 BW
SB
SINCLAIR USER Moy'lSMf*
business
-
ANY COMPUTER which is to
f\ be used in real applications
* ^must be reliable. The ZX^Bl
has a less then perfect reputation in
that respect but all the problems can
be solved; we will see how.
Essential requirements for any
computer are that all calculations
must be done correctly; that the con-
tents of memory must be stored
without being corrupted or vanish-
ing entirely; that it must be possible
to store programs and data reliably
and to load programs and data
generated by a properly-set-up
system.
The correctness of calculations is
almost entirely dependent on the
program. 11 is possible for hardware
design errors to occur which cause
odd problems but they are usually
found and corrected by the manufac-
turer relatively soon after the
release of a new machine.
The ZX-81 had such a problem;
early machines did things such as 3 -
U OOWIOOOOOOOOOI = 7 and 0.25**2 =
i. M23844. That was soon corrected
and the old machines were repaired.
Even the giants of the computer
industry are not free from such
problems.
Computers also have idiosyncra-
cies which must be understood by
programmers; many computers can
obtain a number such as 3.99999yy
by adding 0.1 + 0,1 + ■ ■ .repeatedly. If
the program then tests whether the
answer is 4. or takes the integer part,
the result will not be what is wanted
—thai is the programmers
responsibility.
It is easy to design a computer
without the particular feature just
described but that adds to the cost or
decreases the capacity to store
numbers- The ZX-81 has a very good
version of Basic. The handling of
text information, in particular, is
better than most micros, including
some very expensive ones.
The integrity of data depends on
the design of the machine and the
reliability of components and con-
nections. The electrical design of the
ZX-Bl is, in general, good; it is
vulnerable, however, as are most
microcomputers, to strong electrical
interference on the mains supply— I
SINCLAIR L1SKR May 1082
Making sure it
works properly
To run business programs, the machine
must be reliable, writes Mike Salem.
have used a ZX-ftl from the same
power point as an electric typewriter
Switching -off the typewriter while
the ZX-Bl was loading would usual-
ly abort the load.
The components used are general-
ly satisfactory. The occasional rogue
memory chip appears now and
then — in Sinclair and other com-
puters. Usually the problem is inter-
mittent. Tbe chip is perfect when
tested but causes trouble on
warming-up. The presence of a
faulty chip may be revealed by. say.
incorrect letters appearing here and
there in a program, or by the appear-
ance of program lines which are not
valid Basic — invalid lines cannot be
keyed into the ZX-Bl .
In such a case, a faulty RAM pack
must usually be exchanged or
repaired. Rogue chips usually make
themselves known fairly quickly. It
is also possible for tapes to be pro-
duced which load perfectly wilh
some recorders but which cause pro-
gram corruption similar to that pro-
duced by faulty memory chips— or
simply refuse to load— with others.
That is more common with dupli-
cated tapes than with recordings
[i:imlimi**t\i>n page 59\
57
rsa
ai
REFRESH mut
UKROF
Do you feel you could get more
out of your micro 9 Perhaps new soft-
ware would improve things. Or how
obouf expanding with new peripheral
or more memory 9 Maybe you even
need to upgrade to a better machine.
Then you can't do without
Which Micro & Software Review, a
brand new magazine which doesn't
dabble in micros, it writes about
nothing else.
Well give you more software
reviews (especially tn the bw-cost
field) than any other magazine,
with a unique buyers guide to
software packages, that is updated
every month. Wfe'll tell you what's ava
for each machine, what's in the pi
what's right for you, where to get it,
what it costs.
V\fe'll not stint on hardware
coverage either Not only will we publ
the most extensive buyers guide sect
available but also reviews that take
machines apart. Wfe'll compare cost c
performance, point out compatibility
problems, what's possible (and what
plus our best-buy opmions.
With all this you II get regular round-ups of spected experts in the business. The first issue is
new peripherals, literature reviews, and problem out on April 15 from all good newsagents. Or use
pages written by two of the most re- the coupon to take out your own subscription
WHICH MICRO & SOFTWARE REVIEW
-_ uffi* '. THE A TO Z OF MICROS.
I would like to subscribe lo Ihe firsl 6 issue's ot Which Micro
& Software Review I enclose a cheque for E^ 00, payable lo
'Which Micro & Software Review'
Name
Address .
Send to. Which Micro Subscription Department, Competilion
House. Farndon Rood,. Market Ha rbo rough, Leicestershire
Bfl
SINCLAIR USER May 1982
fcantbtued from page 5?\
direct from Ihe ZX-fll In ihe shod
term, reliability is improved by load-
ing til the highest possible level. In
Ihe longer term, such tapes must
either be re-recorded by the user or
replaced by the supplier. The choice
is the user's.
The most serious problem with
the ZX-61 has been the sudden loss
of all the contents of memory. That is
due almost invariably to the connec-
tion between the ZX-81 and the"
Sinclair RAM pack. This RAM pack
plugs into the ZX-81 but has two feet;
when the keyboard is used the RAM
pack and the ZX-81 move slightly,
relative to each other. One of the 43
connections may be interrupted
momentarily, with catastrophic
consequence for the contents of
memory.
A number of ways of circumvent-
ing the problem have been publish-
ed—we will not repeat them. The
best solution is to use a RAM pack
which employs a tight connector tit
high quality with gold-plated con-
tacts and which does not in anyway
touch the surface supporting the
ZX-81.
The final problem is saving and
loading programs. That can be done
very reliably using simple and
inexpensive equipment and tech-
niques. Use a mono — not stereo —
portable cassette recorder known to
be suitable: it need not be expensive.
Try to adjust, or to have adjusted, the
head azimuth angle. Make sure that
your leads are in good condition. Use
good quality tape, C60 or shorter —
special computer tape is not
necessary — but do not use bargain
tape, although il will in most cases
work,
Make duplicate back-up copies of
important programs an d data. Use a
special loading meter when loading
cassettes of unknown properties.
Clean the heads frequently and
check them for wear as this is a
problem.
One or more ZX-flls can be used as
dedicated machines, running 24
hours a day. Occasional tape back-
ups should be made — the recording
can be started just before a tea break,
for example. If the power supply is
less than 100 percent reliable. 8V
worth of heavy-duty re-chargeable
battery, with trickle charger, will be
the solution.
While the ZX-81 becomes per-
ceptibly warm, overheating does not
seem to be a serious problem; it is
possible to use a true 8V supply,
rather than the 9V nominal, 11 V
actual of the ZX-81 supply.
The ZX-81 can be made to operate
very reliably. The expense and
trouble involved is not great —
certainly far less than that involved
in living with an hopelessly unreli-
able system.
TURN 'LISTINGS' INTO
DYNAMIC ZX GRAPHIC PROGRAMS.
you need is a pencil, ingenuity, and Prim 'n' Platter Produeis!
Wilhin hours you'll discover all sorts of ways to change "wands" inie computer "pictures.'
and produce raa'Hy dynamic ptOfjraflttl
An i Effil do it easily wilh The help of a PRINT 'N' PLOTTER
JOTTER and FtLM.
Ihe JOTTER is a 1 PC page Graphics Pari designed for ihe
3(81 /BO. bisp( page has a PRINT and PiOT grid showing
ihe screen locations.. Ii tells you any part of ihe screen in
seconds, and gives you a 'sketchpad' to produce incredible
graphics for games, business programs, inlormairan
paneks, tabulations everything ltie normal 'listing' lacks!
PRINT N r PLOTTER FILM ia used with ihe JOTTER and is e matt, transparent, lilm
i/eraon wilti identically -sued grids Use il Id co-ordinate PRINT of PLOT, or use n 10 'r.opy'
photographs, maps, charts, Altering or illustrations Id use in programs. You can draw on ihe man
sortaca, and rub-oul or wash it and use again' Print 'n' Plottei products will help you produce
dynamic programs, whelhei you're converting existing listings qi wriliog an ongmaJ
Ask lor ihem at your local Comp Sfiop. or send today ftx mail order.
m
good news
■*■ FOR *.
PFW1TER
omnERe
2hote#
punched- q
Numbered
PLOT Grid-
Numbered
PRINT Grid.
♦ ZXB1
Keyboard.
Program
notes space
100 Sheets, Size A4.
Board backing.
II you do r»t wsh to use this coupon wile, stating your requisition!!..
To-. Prim 'n" Plotter Products &J l<f finraudi Hirjn Sireei, tontton SET BSE
aPte^sandme, J0nERS@E3.5fl D PIbbb sand m . HLMS@C2.25
. : Please stnl m . - MANUALS @ ri.0QiC1.50il ordered without JOTTER or FILM!
□ HenwrtareB erdtised nBlmyAnmrYsaNo:-
SMiir
HotxMn in uuwllv pmlml mllHn « **tu * nn*l. If IM mm l«i Chafni plant Hi Up re nrdu
"im
SINCLAIR USER May 19B2
ftuifcr Ht*.i S*o* 174j SrrnHiM HihSfl L-ondOfi 5*16 < Dtmv TBoOkW**! i Uarthuikni 51 UntaEl- Micrawwa 121 Vena* Alt iKlllr
SB
competition
Write a progran
and win a super
Sinclair printer
Thank you for your entries in our first competition . , , the lucky
winner of a Sinclair printer will be announced next month.
The prize is the same in this month's competition. And all you have to
do is to submit the best NON GAMES program. And because you can
use up to 1 6K all entries must come in on cassette.
The closing date is May 1 2 ,
Fill in the entry form beiow and while we will accept a cassette it must
be accompanied by a well-typed or beautifully hand-written listing.
Your entry must reach us by May 12.
As a tie-break — if one is necessary — we want you to write a slogan
beginning with the words: * I love my ZX-82 because ....... \
The usual rules, about the editor's decision being final and employees
of ECC Publications being ineligible, apply.
— ^^^^ v l \ove ^nV
— - tTVrtflM ... .. „„d « • «* M ' \
; C ompv^ eVhls
ECC PubUcaUonS
Name
| jvldvess . ■ ■ • • •
30
_ 3l \sUngt 0U
Green. ^
dQB
1
1
t
I
1
-J
SINCLAIR USER May 1982'
books
A teacher's view of
the Sinclair
Another batch of books comes under the
scrutiny of reviewer Tom Vests
SOME PEOPLE cannot help
taking their Sinclair micros
seriously, while others find it
necessary to inject elements of
humour and occasionally farce into
their dealings with the machine.
H is a tradition dating from the
early days of the big mainframe
computers. Computer people then
were sharply-divided into two
groups. One resembled the popular
view of a trainee bank manager,
while the other was a band of cheer-
ful or manic individualists. Both
groups produced equally good ideas
and programs.
Those Sinclair enthusiasts who
are writing books on the machines
have already divided into the tradi-
tional groups. While this reviewer
prefers the exuberant individualists,
it is all a matter of style, People who
approach programming seriously
derive just as much pleasure from it
as those who take it in the spirit of
Monty Python's Flying Circus.
Publishing house Macmillan
leaves no doubt as to the approach of
Randle Hurley s book with the title,
The Sinclair ZX-fl I— programming
for real applications. Other computer
titles from Macmillan include three
manuals on Basic programming and
one on digital techniques.
Hurley has aimed his book at
someone who is not a computer
expert and who has read the Sinclair
manual without understanding
some of the more esoteric functions
and techniques completely. More
significantly he adds that the reader
may be a teacher, as he is himself.
The programs and techniques are
based on his experience with the
ZX-81 at his school. He assumes that
the reader has the 16K RAM pack
with the machine.
It is not a book for the small busi-
nessman or club secretary who
wishes mainly to have a system up
and running and to acquire a lh tit*
programming technique on the side
but it is one for anyone who wishes
to extend their knowledge of the
Sinclair and wishes to make use of it
in a practical way. It would certainly
be useful for any teacher who
wished to make use of aSindair,
The tone overall is schoolmaster-
ish in the best sense. Hurley lets you
know what he intends to do and then
shows you how to do it. At the begin-
ning he provides a large number of
tips on how to approach program-
ming, particularly on the most diffi-
cult part of all in writing long
programs — how to keep track of
what you are doing.
He blasts through them at a rapid
rate to reach the heart of the mailer,
programming techniques; many
users will probably find themselves
back-lracking to pick up that wrinkle
on program documentation they had
forgotten but no -one will be able to
say that they were not warned.
Programs of particular interest to
teachers include rank ordering,
examination results analysis and a
reading age program to accompany
the low-grade word processing
system. Hurley promises a mor<- use-
ful version of the latter in a book
being prepared on ZX-B1 machine
code.
The programs and the listings all
illustrate useful techniques and the
lines of program code are explained
comprehensively. line-by-line — a
major plus in books on the Sinclair,
In keeping with his aim of hefThg
the reader push the ZX-81 much
[continued on pnge ti2\
rggj
SINCLAIR USER May 1982
61
Ml
(continued from page 6! J
further than anyone expected when
it was launched. Hurley offers a
number of hardware modifications
in the last chapter. They are a modi-
fied power supply, extra money and
hooking the Sinclair to a standard
keyboard. They are not fur the elec-
tronically-illiterate and require the
ability to read and understand a
circuit diagram, as well as to solder
neatly, which Hurley suggests as the
only pre-requisite,
Where Hurley employs 160
pages to show programming tech-
niques gently, Andrew Hew son
takes his readers through his Hints
and Tips for the ZX-81 at a gallop in
75 pages. The book is based on one of
the same title for the ZX-60 with the
requisite amendments and. more
important, deletions.
It is not designed for Hiiyane who
has yet to bang their heads for about
50 hours working-out Basic pro-
gramming techniques. Most of it
consists of solutions to problems of
which the beginner is not yet aware
and explanation is kept to a
minimum.
The general style is along the lines
of "So you ran into that problem,
loo— here is the solution which
seems best to me at the moment Oh,
and by the way. here are two things
to avoid because they can really tie
you in knots'.
There are good, sound suggestions
and techniques in the book but. in
my opinion, it is designed for the
committed and dedicated, although
others could find it useful as a
reference.
[ liked particularly HewsOft's
warning about machine code pro-
gramming — "Unfortunately wriling
lengthy programs in machine code is
rather like solving 7 'he Times cross-
word, It is a pleasant intellectual
challenge once you get the hang of il
but until that time it can be a time-
consuming and frustrating busi-
ness. They are worth keeping in
mind.
There is very liltle to say about
Mark Harrison's Byleing deeper into
your ZX-81 beyond my opinion that it
is one of of the best manuals on offer
for the beginner. II assumes a small
amount of general knowledge on the
part of the reader hul starts by des-
cribing what a computer is and leads
through to the most advanced tech-
niques of program m i ng the ZX -61 ,
For an yone who has always avoid-
ed all things technical, Peek, Poke,
Byle and RAM by Ian Stewart and
Robin Jones would probably be a
better book.
Il makes no assumptions of
knowledge and is well laid -nut.
The idiosyncratic asides along the
lines uf 'My cal did such and such'
could be irritating to those who dis-
like that kind of thin^.
r
LEISURE GAMES
> ft ware for Hob I
>mpi;
THE KEVS OF GONDRUN
A -oumey beneath the Enchanted Forest in search of the
missing keys of Gondrun The Wizard. Can you discover the keys
- and stay alive? With real time monster fights (6 skill levels).
save on cassette feature and alternative responses to give a
different game every time. Map the cave? as you travel through
them, but beware of the Two-Headed Thronga, the Jub-aroo
and the other nasties which are lurking. A great game occupy*
mg The fulll 6K RAM.
PACK CONTAINS TAPE & INSTRUCTIONS Only £5.50
POP STAR
Would you like to be rich and famous? This program won't
guarantee thai, but it's great fun all the same. Will your records
be hits? Can you negotiate a better royalty rate and increase
your i nc om e ? M aybe you" H be offered a TV se nes or f i I m B ut it
isn't an easy life and troubles, like flop records, the tax man and
o the r horro rs a re a Iway s w a i t i ng . A nd hf you dec ide to b ribe a nd
cheat - then don't get caught' In this game you could make a
mill ton -or you could end upbroke. It's up toyou. Requires 1 6K
RAM
PACK CONTAINS TAPE & INSTRUCTIONS Only €5 50
SPECIAL OFFER
Both tapes supplied together for just CI 0,00
We may have other games ready by the urne you read this,
S A t fordetails
All our prices include UK postage European customers please
add 2 Op per tape, elsewhere please add 50p per tape
MAIL ORDER ONLY
LEISURE GAMES
3 Spring Rise, Hiqh Crompton, Shaw, Oldham, Lanes
COMPUTACALC ZX
^^^rja
t>£C
JftNi
FEE MM.
FiF'T
|r-10RTGHBEl&7
167
1S7 167
167
ie
If HONE
ta
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Igr=
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31
JCLCCT
4-3
'?«"'
ICflFJ
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71
££ fit
65
jINSUR
is
1.9
X3 IS
12
IS?
Irrtcs
ec«s
SfoTHL
20*
393
S*« B7*
a*4
37
An advanced spreadsheet program for the Sinclair ZXB 1
with 16KRAM.
This versatile software allows manipulation and inspection
of data fn the most convenient way ever. Ideal for financial
planning, personal budgeting, cashflow analysis and couni
less other business, home, scientific and technical
applications.
The screen acts as a window on a much larger grid jup to 38
k 38) of titles and numbers tup to 9 digits} Change one
number or formula and all dependant results change auto-
matically. Save on tape or printout for a permanent record.
Tasks that would take hours with pencil, paper and
calculator can be performed in seconds with
COMPUTACALC ZX
For cassette and full documentation send €7 95 to: Silicon
Tricks. Dept. 52. 2-4 Chichester Rants, London WC2
1EJ, (Tel: 01 603 6074.
B2
SINCLAIR USER May 1882
1KZX81
ADULT GAMES
tOtt JADtQ MINDS. 6AO
TASIfr IS OURlPKiAlHV
f
ACNE VASECTOMY SMUT
1W
HOVAL FLUSH REAGAN
HITLER
PVNQs
ffi* ^& J)E ATH
4fOUCflON fO«CtPT)OH W*TH
hubksBuse
CM THE KM
itiuiit No.3
■of fh* crtw 16'%
£5.oo
THE BI&LE
GENESIS ADAMUEVE NOAH PLAGLCS EXODUS
Ho»y Moses SODOM GOLIATH JONAH Bethlehem
pi ii*t -k ludt bijeirr audio MMB rnofringlj drit'ipuve «w.fruclnm», p<Mlo9« * patkoqa.
und »e fcUfOMAt* LID. IQfH Z I, *S* Otfce»™ S™». f*»l«noylh POi JUf, Hanli
FOR THE 16K ZX81
UNBEATABLE VALUE!
CASSETTE OF 8 PROGRAMS (50K+)
For fun and fortune- no programming knowledge
needed!
ONLY £5
DEEPS) \ kDVI NT! Hi n4K)Dfeeoverthe treasure chert
before you run oul oJ paid or strength. Lewis i'i ptfl) from
"diflicuh" to "downright impossible'*. Aba has "Save Game"
feature.
BANK \t. tt)t NT iLV'rki Invaluable Ibr controlling >our
finances Produces detailed statements and c*nabo keep track
of credit card spending.
I Mll-kdRUIND AOVENT1 fc£ (rt'AK) BaUla ■<
mongers and obstacles underground. A very difficult and
thallen&inglask.
Itf-I'l IK HAH i rt (2*AK) A skillful moving graphics same.
Fire your deptftchacges to blow up enemj submarines before
[hey destory yOurilup.
HANGMAN (II '■',■ K) The old family game based on a library
of Mu words. Excellent graphic.
LOAN (2 VbK.> Calculates repayments, umesum borrowed or
interest. For Bank Loanser Mortgages
■ ■ IDEVRE \K1 K i 2 k i You have ten guesses a( the fitur digit
nunther held by the computer.
FOREIGN CURRENCY i !K) How many delist is II 10'.'
II. -m mans Francs is S38? Sec what your money will buy
around tin- world?
ORDER NOW!
For convenience simply quote SU4 and your name and
wJdrea »a the nrwsrse of your cheque/postal order, and your
software (on I DK Cf£Ktte) Will then QC despatched, lirvl eksa
post. ccimpleiewilhanMpichriiMve instructions.
Send to: Richard Shepherd. 22 Gram Leys,
Maidenhead, BerfcahweSi* 7EZ
K'kphone:|062*!)2ll07
Microgame ZX81
Simulations (16K)
Soccer Supremo Run your favourite club in your own style,
controlling game strategy, watching your team play other
great sides in the Super League, transferring players, including
star names, making boardroom decisions or delegating to
solve business problems; improve facilities; spend gate money:
lots of The fun and headaches of the soccer boss's lifestyle
Includes graphics.
Balance of Power As leader of a superpower you strive to
maintain superiority of arms over a neighbouring country The
problem is that you and your enemy are mutually dependent
on each other for raw materials. Can your economic, diplo-
matic and military judgements prevent a rapid slide towards
nuclear war? Use threats, sanctions, force, tactical
concessions etc.
Tycoon Start a company producing "widgets and compete in
the market against a computer controlled rival Sort small and
build up yout business or borrow money and start big You ha ve
to make decisions about financing, staffing, factory space,
machinery, pricing Etc.
Battle of Britain As strategic commander of nine British
fighter squadrons you must track and intercept the devious
enemy bomber squadrons before they reach London. Micro
acts as a flight control and communications centre for
patrols, missions, intelligence reports etc Sketch map
provided. May also be played on any map of SE England with
standard gnd
Asset Stripper Compete against your computer controlled
arch-rival "KO Investments", capitalizing companies on the
stock market and bidding for takeovers to gain control of
lucrative assets. Can your micro really outwit yon ?
Kingdom of Nam As ruler of Nam you must control its
economy; allocating labour; building cities, factories and ships,
importing and exporting; negotiating pay claims and fighting
the looming threats of inflation, strikes, starvation, over
population and revolution How long can you stay in power?
AH programs 1 6K for 1 player
C4 95 for 1 /E8.90 any 2/£ 1 2 85 :3/£ 1 6 8O:*/t20.75:5
Please sendcheque/PO to;
i 73 The Broadway. Grantchester, Cambridge CB3 9 NQ
REGISTER
brings together the Sinclair ZX world within one cover
DIRECTORY OF 350 SUPPLIERS
Schedules of SOFTWARE programs
Games, Educational, Business, Computer
Enhancement and Domestic sub-divided
into a further 30 categories.
Extensive list of HARDWARE items for safe
Index of ZX PUBLICATIONS
References to reviews of ZX ware
USER CLUBS — when and where to meet
Much other useful information including details of
other services and programs, notes for new users,
advertisements.
Price £2.95 from
YOUNGS ZX REGISTER
2 Woodland Way, Gosfield. Habtead Essex COS 1TH
The register is being cnntinuouBty revised and re-isso***^
If you want your new product to be in the Register contact us
We con also arrange for you to be on PRESTEL
SINCLAIR USER MayiM2
83
personal computer software
ZX81/16K SOFTWARE
"STARTREK"
1 6K STARTREK: Ek citing space adventure gome including
klingons starbases, phisors, B ■ x B galaxy. 4-tevels of plav,
long and short range scanners, etc.
"SUPER-WUMPUS"
16K SUPEH WUMPUS: Can you hunt and catch the
mysterious wumpus in his underground labyrinth? Intrigu-
ing u nd ergrou rid a d ven t u re.
"GRAPHIC GOLF"
16K GRAPHIC GOLF; Test your golfing skills on
SILVERSOFT'S 1 8 -hole golf course. Many hazards includ-
ing lakes, trass, streams, rough, etc.
"GAMES PACK 1"
16K GAMES PACK 1: Fantastic value for money, nearly
50K of programs on one cassette. Five games including
"Real Time Graphic" Lunar Lander, Starwars, Hammurabi,
Minefield, Mastermind.
"3D-MYSTERY MAZE"
16K 3D MYSTERY MAZE: Amazing three dimensional
maze- Walk through the maze in 3-dimensions. ultra-fast
machine code display, hundreds of different mazes.
"ZX-ZOMBIES"
Can you escape from ttie man-eating zombies by leading
them into the pits-? Eight levels of play. Very frustrating.
SILVERSOFT (Depi SU5I
40 Empress Avenue, llford, Esse*
N E W! N EW! N E W!
ArCdde GameS (all entirely m/ecodedf
"SPACE-INVADERS"
Simply the best yet,, the closest thing to real Invaders an the
ZXB1. Full arcade features! including 1 or 2 player option
and software to drive theQS character-board.
"ASTEROIDS"
Authentic representation of the arcade game including
L R, thrust and fire controls, 5-levels of play and alien
spaceships,
"DROPOUT"
Exciting new arcade game. Can ypu destroy the aliens
before they build up in t h ei r columns and overwhelm you,
Prices: ASTEROIDS. DROPOUT £S,95ea.
OTHERS £4,95ea
When ordering 2 or more deduct £ 1 ,00,
S end S . A . E for Cat alogue ,
Chequ es/PO s payable to ' S I L V E R S FT' ' .
Name
Addreis_
WANTED ^X6l.VIC-20andSU/&, BBC Micro Software
Exes Hen! Royalties - S,A E lo'dttulf
^Boftwar^
Quality SoPtuare
' tb& v& btxjgfir fltlflWM/S GmffJ ttvmi nt .YnffWare t Pur* 8t8€*&Qften1
They LOAD iwll twv* parted mstructhnt th*masiasi>r-trten<tl\ttha-ve
evef m*t " ff* R Motif I
zxsil6k RAM Pack T^
tiwluiiniff riTCT "iHiJirr lKTtrratj- »iHti« ^*
clXol soPtuare
GALAXY INVADERS I rnqu irps minimum 4K RAMj in mflcrnnfl code
Cijuitfe ,>ntf .nstrudajris. . 13QQ
1 K GAMES I Duck BfewL Mocmlandar Hangman. Cnjjswmi Letter- Square I CM**R*
irwtivctiom F3 OO
"Frvwflg "GAMES' vavy modi- IttmSttuate'tsQuueaoaitiive
"I tMvtfi/st rttstvsdynur mmH at GALAXY fiVVADERS yrtucti I think is tf»
6*a r art the market . Itm <t*ry pleased nwihyuur uunefr sexier " (S.C. Beds J
MUITIGHAPHICS 2.3 (requnfls minimum IQK RAMI crn»ie drawings, adv*n«ing.
display! els. an screen. Diaplay&eanbflSAVEd an t«p*. printed pnynu.rZ>(Prmrfir.
CaratH-inrtiOpjaerllusi^aced Manual Tt &D
"MSJt-TtBRAPmCS ismoft'mf/retsiveBntiftaictoannslrvct'ons "
ffncOttltm. "You/ Computer " Frhlutty 1 98.2)
1 K GRAPHICS IK aieiaoscope. Large PmH, Mwdiu m Print. Draw A Picvj re
Manual pnlYieaniainsaCCUfat9listinfl.n0tm, inli>rrn»tinn andidn?5-l
Cas*e!l€ andin»trucl-una
Package n'panseH" end Manual. . .
1K STATISTICS 'A p'og'ams. desenpfme and inferential slats)
Caisene and inslnKtions ■ ■ ■
Booklet comaming listings , ieii data eit
ZXSO snftwarr pi id avliltble
5e-nd»J* l?r'ur|hrrdsU4l
BRIDGE SOFTWARE (U)*w«idir«i**
36 FERNWOOD, MARFLE BRIDGE,
STOCKPORT. CHESHIRE SK65B^
I * iivMirft* VAT. pQfir and packing in U K
Eumpeir Lu&ro inert add 3Pepi' ir«m. Worldwide ?Ppp*f lEim
£3.00
£3.00
fAiiO
C3.0Q
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,^af"n "FFi\n, i r\ n t~
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CjS^ RETAIL SHOP
w IN
LEICESTER
FOR
ZX81
LU
<
o
o
ACCESSORIES
KEYBOARDS, RAM PACKS,
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S.A.E. BRINGS CATALOGUE
73
m
MICROWARE
131 MELTON ROAD,
9-30am- LEICESTER Closed
E-30pm TEL681812 ThufS
MICROWARE
84
SINCLAIR USER MdylBB2
mind
games
•
Teaching Sinclair
noughts and crosses
Philip Joy describes how to make the
ZX-81 learn from its mistakes.
HOWTHE end game of chess as
played by a computer has little
skill involved was explained
last month. Most tend to advance
their pawns as top priority, which is
satisfactnry if the other player lets
you do it; mostly, though, he will
have you in checkmate while you are
messing about. Now I am going to
tell you how a computer can be mad«
to learn its mistakes and so build its
skill factor.
The game in question is Noughts
and Crosses, which you may say, is a
simple game. In fact it is, but if you
have ever played a computer version
of the game, it lends to be very easy
to beat. That is because it is not a
game of chance but simply of using
thecorrect moves at the proper time,
a game of total skill not counting the
chance about where the opponent is
going. It is that fact which can lead to
a computer learning its mistakes,
hence finding all tho correct moves
and hence having a perfect skill
raling.
To make the computer learn its
mistakes requires very little work. In
simple terms, the computer, if it gut's
first, can go in one of nine squares to
start, one of seven squares on the
second move, and so on.
To see which square it should
choose, we must look how a human
player would make his move, One
thing he would do is to look at the
computer's move; that is the single
must vital point affecting the square
where yoo go. When we had seen
what the computer had done, he
would use his judgment to decide
from past experience the best
square- The word past is vital,
because it is no use knowing what
square the opponent has chosen if
you do not know the correct
response.
Therefore for each move the com-
puter would have a list of moves for
each move the player made. They
can be produced at random at the
start of thu game. If a game is lost, the
i ompuler's last move la thrown out
and a new move put in its place
which has not been tried previously.
If all the moves have been tried at
that point, the move prior to that is
altered, In that way the more games
played the computer will show more
skill, until it should be unbeatabh
This type of game can be put on
any microcomputer with about 16K
of memory; you might like to try it
using your ZX-81. If you do, I would
be interested to see it and 1 could
include part of it in one of these
pages.
Next month I hope to produce a
listing of a game called Nim, an old
game about piles uf matches. Two
players Lake it in turn to take some
matches from one pile at a time,
There could be nine piles, for
example, with say six in each, or any
other combination. There are usual-
ly restrictions on the number of
matches a player can take, say one to
three per move,
The game can be put on your WK
ZXnBl with no difficulty. In the
meantime, you could try to produce
such a game which you could com-
pare to the uric I have written,
Your ZX-fil is perfect for produc-
ing such mind puzzles as anagrams
and missing number sums.
1 hope you can send any mind
games 1 have mentioned so 1 can
include them. I would also like to see
any games you have played against
the ZX-81 chess programs, whet In i
against yourself or computers.
Advertisement Index
Abacus Electronics
Addictive Camas
A.P£. Software
ftrlic Computing
Automata
Bridge So ft wart 1
Buffer Micro Shop
Bug Byte
Butler, Currie& Hook
Cap
Computalulor
Control Technology
D-K. TronicS
30
Em jay
56
FroiiiH Computing
40
Fuller MicroSystems
40
P. Furlong
63
J, Gibbons
64
l.K.Creye
25
S. Hessel
2
Hewson Consultants
59
Holdco
13
I.R.S. Software
52
Kayde
67
Leisure Games
4
Lin sac
25
Macron ics
10
(JuicksilvB
B
30
Memotech
e
Redditch Electronic
26
25
M icrooomp ut er S a ft wa r e
41
R.Sheperd
63
56
M ic rog ra me S im ulab on s
63
Shiva Publishing
52
41
Microgen
40
Silicon Tricks
62
29
Microware
64
Sil verso ft
B4
17
Mindwsre
41
Sinclair Programs
52
21
Moviedromi! Video
56
Sinclair Research
46 b 47
16
Newnes Technical Books
21
Thurnall Electronics
39
Oasis Software
56
Video Soft wan 1
68
M Or win
30
Which Micro
5B
52
Pheonix Marketing
3H
Workforce
41
10
Picturesque
39
Youngs ZX Register
63
SINCLAIR USER Mo y 1982
65
ZX80-2X81
HARDWARE
Tape recorder interface unit Unsigned
to help those with LOADING diffi-
culties. Self confined ai £ 1 Z.50 inc.
Video amp. unit to allow ZXS0/S1 to
drive standard video monitor Much
better pictures than on the TVs. Self
contained at f 12 ,50 inc.
DETAILS ON KEYBOARD SQUMO1H5
SAE FOHIMFORMATrQU.
0. BRUCt ELECTRONICS
The Beacon. Blackball flock*
Cleveland TS2 7 48 H
Tel 0-783 S636T2
Caiiatta A: 20 Sup*r I K Games. Som b
nvng mauhina cede Moving graphics
ana ihmkars' games Superb vaule,
on1>'C2.75
Casnetie 9. Mine invaluable t£K
ur'lirii?s*rid»fiheneemeflis.o.s| 4 vvay
*rm|i rtnumbtr Occupies v 3 K Too
man ( features Id list. Includes Demo
Prog. Aanipa<C3.2 5
Caisene C. Great machine code
editor. Far ttrt many features 1n li-st A
musla! only f 3 So-
Phone 02 34 46248 lor tJelai Is
AH progs recorded twin* on TDK i tapes
Send cheques or P.O. to. B. Rao. 12
Parkstone Close, Bedford, Beds
MK4.1 BBD
I
NEW&OFT PRODUCTS FOR TH|
16 KZX 91
RAMPAGE: Wum-cwy mapped Adventure
in your IX -81 Peek end Poke your way
around memory locations in regain full
conn at al your R*m pack Bun. Poke or
Crash rival Home computers Reward
a friendly IK SO with spare Byies
This superb new game i S an educariort
as well asan adyenlure.
TIME BANDITS. A new idea m Adven-
ture games- two programs for the price
of one 1
Side A holds frve new fl»rntjl Mmalau-rs
Labyrinth, fowoi of London. Castle of
Evil etc Use the individual Hemes cm side
A tor preence before running side 9.
On side B the game* are combined into a
free! newi adventure Kidnapped by the
ime Bandit* yew must battle your way
through Time and SpAr.e. Fight the
baddies and defeat 1 he Pnnce of Ultimate
Evil i
ROULETTE: Net the usual Comir..'ei
ffoulstta. This cuogtsm is a complete
simulation rjt the raal game Accepting
all legal Pet*; tingle, double, triple
nufnber bets, red/b'ac*. odd/even, high/
low and more' One or two phwwa,
multiple bets on each spin of Ihe wheel.
Juii like (he real game Can be used lo
te-51 any system i
COMING SOON- VALLEY fnrthe
ZX-fll.
The traditional Adventure gam* in 1 fj. K
Castles.. Towbt*. Temples, woods and
amps. Ikghl Monsters m Heal time,
■h 'or Jewels and Amulats
. need 1 0-K. 5AE tor details.
hVMr ' 5 Mth. any two Tor £4 aa<h
N-WSOFT PRODUCTS
12. WHITE B ROOM BO AD. HEMEL
HEMPSTEAD HERTS
ASTRO-INVADERS
(16K)
Su-penor machine code programming.
fast action space g-raphuis. a new
dimension inZX-8 1 valu#:
4)54m anoeu vnng aliens
• :;;: igsaucBrs
*) phatpn torpedo fining
• cffllence shields
• on-screen kill enuni
On cassette with four SONUS
games. ARCADE GRAND PRIX
'machine code skill 4 levelaj,
PENALTY I get ready for Spain 'B2!>,
G OLF | judge jhoi strength, a nglat,
bunhen and maybe hole in nne!)
p-lue run SWAT.
5 games on one casssuif lor only
£3.65 ipost treef Order now from
John Prince, 29 Brook Avenue.
Levenshulma. Manchester. M. 18.
V.D.U. Screens
Fit over your T.V screen! Add colour
lo your computing with professional
sTylo screens in hard perspen in
Green, Amber of Blue These screens
coma complete with finer* to your
exact sue requirements Price up to
1 1" x 9". f 5 95 or up to 15" * 12".
E7.9S. State size and colour required.
PriC e includes postage and peck ing
P. A Voting - New House. Church End,
She-tiff Hutton, ¥o* YC"B 1 PX
2X81 M&K; tOUCATIONAL
SOFTWARE
G C E "0" LEVEL MATHS: 3 ii.ll IGK
n rtiy rd mi ranging over whole »Y"*buB-
JDMIDR MATHS V Long Mult, Long
Oiv. HCF, LCM, Fraction* 1 ( t A _|, Frac
tions2(x* - ;■
JUNIOR MATHS 2. AnMa, Perimeters
Sintplir Equations. Rereen leges, Sets.
Venn Diagrams
JUNIOR ENGLISH 1 Minings I.
Meanings 5 lharderi. Paris ol Spe*ch.
Proverbs. Sim lies. An agrams
JUNIOR ENGLISH 2: Idioms. Opposite*
1. Opposnes 2 (Itardrer L Group TBrms.
Odd Word Out. Spellings.
£4.50 iiet <as4elfe or sand sae for
catulrjguato:-
ROSE CASSETTES. 1 48 Widnay Lanr.
Solihull, West Mid.la.iKts 691 3LH
1X81 IK
starter pack
Twelve program* on casse'tia written
in 1 the nam user to demonstrate the
versatility ol theZXfll. Seven aucm rig
moving graphic games inch,,
invaders. Tank-ShOoL Subsearch and
Roart Race A sound unneration
program is alto included.
OroWi rlir^jjarchetf art high quaint
c flsjrwr fry return. O SO with cvafcw rs
Timnwtli. Slat*,. Bf) ILL
ALGOR
16KZXB1 andZX80 8K ROM
PROGRAMS ON CASSETTE
19K81/1 - £3.60 MIMES AND
MONSTERS (| to 4 ptayersl. A narra-
tive adveniLim gams of monMer killing
aFirttreasurehuninK;
STOCKMARKET il to 4 players! make
your forliine Oh 1 he stoc k enc-hange
16KB1 2 £3 SO SHELOB'S LAIR lt,i-
pictorial adventure game with compieie
room structure. Choice of weapons tor
battling with the denuens or the lair
ECONOMY GAME: II to 4 players) Can
you set the economy tn rights and oui-
persuade your opponents 10 wm at the
nejrl Ijeneral Election) You may lie a
httle
If KB1M- £4.M CHEOPS TOMB: ft
To 4 piay#rs) Compete wnh your oppon-
ents 10 get pest the old Gods to the
sarcophagus and thu<t find the only
means of escape from the pyramid wnh
all your wealth All rooms drawn as if thftv
were real 1
COMMODITY GAME 11 to J plftyeral
Brd for Contracts of Supply against your
opponents. B-,jy materials on the marital
at a bargain and srll tor ma sS'VS profit
16K81.-X - 16.SO. COMPILATION of
gftmes for 1 10 4 pljiyerB MlhfEE AND
MONSTERS, STOCKMARKET ECON
OMY G AM E anrj CO M M O D ITY GAME
1&KB1/3 - fS.M. MACHINE CODE
SERVICE: Far Machine Coda, Multi by«e
dhijimaF and character enlry, includ**
branch instruction assembler and Label
handling. The prygrom will list any ol the
above data types Other facilities am
ADD data. Mfjvedata and DELETE data
Sen table also for the beginner the pro-
gram c me s wrfh a 50 page ma mu I
1&K8T/5 - £30fl. THE FINANCIER:
Designed to give an insight into finance
calculations Used tocnltulats mortgage
repayments, lerm mvasiments. return on
investments, amortisation and - dis
counted cash flow. Includes graphic dis-
play end formulae
Cheque or PO to AlOQR. Dovarcpunt,
St Jamaf Rd, NorthampTOn N N 5 5 HW.
PrtCa list on request Post and Pack is
■ "•: : n:k-\ Ovaneasadtfl ; ; - 00
ONLY £5.00
PRIVATE ADVERTISERS-DOIM'T LEAVE THATOLD
COMPUTER OR PERIPHERAL LYING AROUND
TURN IT INTO CASHI PLACE A SMALL AD IN
SINCLAIR SUPERMART AND REACH OVER
100,000 READERS FOR ONLY £5,00.
POSTAL ORDER OR CHEQUE WITH ORDER, PLEASE
ZXB1 USERS
FIGHTER PILOT You ere the pilot d'a
(01 fighter. Teal your iriitiurrn-nr flying
skills frcnri fika-eff to landing with ihit
real-nma. 3 dimension«l liight Simula.
lion Supplied an caw<nte for 1BK ZX9-I
«4B
MOTHERBOAHD. Two-slpt mother
board ior eipandms vour fxBl Com-
plete wnh 5v legulatar tD remove the
strain that hardware eirlensions put on
the internal regulator Only £14.91), built
and tested
23-way JX EDGE CON NEC TOR
I 1 49 each
fliciting new h»rrjware and aottwara
p< oduCM m development
ALL PRICES INCLUSIVE
SEE U$ AT THE 2X91 MICflOFAIR
DIGITAL INTEGRATION
22 Ash Church Rd . A*h. Attarahul.
Hants C-Ul^fiLX
Mail Order Only
CROSSWORD PUZZLE for
ZX81 1 f16KK GrapMiCS. Tsais
knowledge of Basic. Also
AN AG HAM Three levels- of play
Two games on one tape fof
£4 95. Computatutor, 3 Trialia
Close, Greenwich SET0 9MA
ZX81 MICRO ZX PRINTER
16K RAM ICLTraining Manual,
other accessories, for sale all
together El 15 o.n.o, Hardly
used, perfect working orrter
Contact Leicester {0533)
892408 after 5pm
ZX81 LARGE KEYBOARD plus
case for £25! Brand new, un
used, 4 rubber feet, custom-
built textured case. 40 well-
printed keys, Easy to fit. Bargain,
P Ralphs, 1 Duxford Walk.
MostonfV1/109JN
NEW GAMES FOR ZX81. I
have devised something differ-
ent which yau can share. For 2 *
1 5p stamps you will receive a
fully detailed list D. Rist, 318
Kmver Road, London SE26 4NT.
ZX81 PROGRAMS One-arm
Bandit, full -screen graphics dis-
play includes Hold Feature: a)so
calculates your money Break the
Bank. Only E500 ZXCALC
Normal Calculations plus sine,
cosine, tangents, percentages-
Only C2.00 Kevin Reed, 129
Amesby Avenue, Sale, Cheshire
M33 2WH,
ZX81 1 6K. Computer + Printer,
3 months old, v.g.c (new ROM; +
lots of software £175 o.n.o.
1E225 newl, might split Call 28
Bgrjkfiurst Close, Redhrll. Surrey.
Tel; Redhill 61612 after 6pm,
6£
SINLLAIR USER Muyim
SPECTRUM SOFTWARE NOW AVAILABLE
PACK 16/1 includes all of:
AIR TRAFFIC CONTROL Animated radar screen of
busy airport shown, you must bring planes into land;
INVADERS SELF PLAY; PHONEBOOK - keep
friends' and relatives* numbers on cassette; DATE
81 - computer dating program Who will it pick for
you?
ALL ONLY £4.95
PACK 16/2 includes all of:
ADVENTURE ATLANTIC: You may become very
rich or you may be marooned forever; BREAKOUT;
SQUASH PRACTICE; LANGUAGE TRANSLATOR
translates any European language to any other;
COMPUTAPRINT - use this program to predict
results of horse races, football pools, etc.
ALL ONLY £4 95
CASSETTE Vh
A super value cassette of 16K and IK software
written in Machine Code a net Basic.
Includes:
React, Invaders, Phantom Aliens, Maze of Death,
Planetlander. I Ctvng, Hangman, Invaders. Laser
Base, rectangle plus more.
ALL ONLY £4.95
PACK 1 6/3 includes all of:
INDI 500; video roadracer; DRAUGHTS; Computer
Chequers; BATTLESHIPS - nautical warfare on your
own computer.
MASTERMIND - Brain teaser, see if you can beat a
microelectronic mind.
ALL ONLY £4 95
The breakthrough you've waited for:
PROGRAM THE 2X81 IN ENGLISH!!!
With GAMAL 81 you can now write adventure
programs in hours not weeks and with GAMAL 81
you' lit have every adventure you'll ever want for the
price of one.
Comes on cassette with instruction book. £7,95
Tapebook 50, Version 3
50 programsfor the 1 K RA M ZXB 1
Latest version includes:
SQUASH, BREAKOUT, COLUMBIA. SPLAT,
INTEGRATION, CREDIT CARD CALCULATOR,
BANK A/C, VATCHECK, TANK BATTLE,
TORPEDO, HEXLOADER, BINARY CONVERTER,
AND LOTS, LOTS MORE
Still amazing value at £6,95 the lot
ZX AUTOCODER
This program takes your BASIC, converts it into Z80 assembly language.
ZX AUTOCODER compiles a subset of ZX81 BASIC tor the following:
PRINT, PRINTAT, PLOT, CLS, PAUSE, GOTO, GOSUB, IF THEN, GOTO,
and LET statements. £6.95 including Cassette and Manual
ZX BUSINESS SYSTEM
This is our latest package which includes all the software you need to use a
ZX81 in a small business. We bring you a full feature system only found on
much larger computers. This includes:
PURCHASE LEDGER SALES LEDGER STOCK CONTROL
MAILING LIST PHONE DIRECTORY
ALL THESE ARE SUPPLIED WITH CASSETTES AND MANUALS
INTRODUCTORY PRICE £14.95
YOU WILL NEED 16K RAM ALTHOUGH A PRINTER IS OPTIONAL
PACK 16/1 + 16/2 + 16/3
(any two only £5.9 5}
ALL THREE ONLY
£695
TAPEBOOK 50.3+ CASSETTE 1
BOTH ONLY
£9.95
All prices include VAT and postage and pecking
CONTROL TECHNOLOGY,
39 Gloucester Road, Gee Cross,
Hyde, Cheshire SK1 4 5 JG
061-368 7558
OVER A MILLION PROGRAMS SOLD TO DATE!
ZX80/1
WAR!
ZX KEYBOARD
FULLY CASED
REPEAT KEY
WITH
FULLY CASED KEYBOARD £37.95
UNCASED KEYBOARD £27.95
KEYBOARD CASE £10.95
This is a highly professional keyboard using executive buttons as found on top quality
computers. It has a repeat key and comes, complete in its own luxury case. This is a genuine
professional keyboard and should not be confused with toy keyboards currently available on
the market,
16K RAMPACKS
MASSIVE ADD ON MEMORY
FULLY CASED
comes fully assembled, tested and guaranteed
The 1 6K Rampack plugs straight into the user port at the rear of your computer And, of course, as
our productsthe Rampack isfully enclosed ina matt black slimline plasticcase.
This means you can handle it with complete safety and you do not have to stare at ugly components-
other makes of 1 6K. The Rampack NEEDS NO EXTRA POWER and will operate quite happily on
Sinclair power supply. Fully built and tested.
Don't forget you can always orderon the telephone with your credit card
Six days a week for a same- day service.
WHY WAIT TO PAY MORE
FAST IMMEDIATE DELIVERY
in all
asm
your
Post to;
DeptSCLJ2,
Kayde Electronic Systems
48/49 Exmouth Road
Great Yarmouth
Norfolk NR30 3DPTel:049357867
All products include VATarefully
built and tested and come with a
COMPLETE MONEY BACK GUARANTEE
' Please send me
| Please send me
Please send me,
I Please send me
RAM packA £32.95 each '
cased keyboardA £37. 95each |
uncased keyboardA £27 9& each
keyboard case A £ 10.95 each 1
' I enclosed
1 Name.
| Address
1 Please add El 50
■ Electronic System*
p/p and make cheques payable to Kayde *
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